dacs.install — DACS installation guide


This document describes how to build and install this release of DACS. Please read it carefully. It is also important to review dacs.readme(7).


  • Installation requires the GNU make command (gmake) and GCC. On macOS, LLVM/Clang is used.

  • Our philosophy is that DACS should be used with the most recent stable versions of third-party packages (such as OpenSSL) available at the time DACS is released. This helps to ensure that a DACS deployment has the latest security features and bug fixes. A DACS release will most likely not have been tested with older (or newer) third-party packages, and the DACS instructions for configuring or building an older release may be incorrect. You may save yourself time and headaches if you just use the recommended releases.

    That said, third-party software used by DACS is often already installed or readily obtained using yum, rpm, pkg, or a similar package manager. These are often not the latest versions, but sometimes convenience outweighs other factors. Provided the DACS documentation does not forbid a particular version and DACS seems to build and test correctly with it, you may elect to use it.

    For a very few third-party packages, it is important that you use the exact version that is mentioned. Do not use anything newer or older.

    For some third-party packages, a particular release is recommended. It is less critical that you use the recommended release.

    Sometimes the recommended version of a third-party package will be fine on some platforms but is buggy or will not build on another platform. Whenever possible, the DACS installation instructions suggest an alternative version, and you may proceed with that version, or a recent version of your choice - but keep the preceding comments regarding older releases in mind and ensure that a "gmake test" of DACS completes successfully.

  • Should a critical bug in a third-party package be found, the Post-Release Notes section will provide instructions.

  • You should build third-party packages in the order in which they are discussed below because packages that are discussed earlier may require some that appear later.

  • The examples here and in other DACS documentation assume that DACS is installed in its default location, /usr/local/dacs. If you specify a different location at build time, please keep this in mind as you read the documentation. This also applies to third-party packages, which you may install where convenient, provided you are careful not to confuse or combine different versions of the same package; in this document's examples we install them under /usr/local and unpack their source code under /local/src.

  • In some examples, long lines have been split to improve readability. Copy-and-paste with care.

  • Whenever you upgrade to a more recent version of DACS, do not forget to install the mod_auth_dacs module that comes with your new version of DACS. DACS web-based access control (dacs_acs(8)) will deny all access if it detects an incompatible version of mod_auth_dacs.

  • On macOS you will probably need to install the Xcode development environment.

  • On some platforms, the PAM development environment is required if you need DACS to authenticate against Unix accounts. If security/pam_appl.h is in a standard include directory, as is often the case, it has probably been installed and no action is necessary. On platforms where this development environment is optional (CentOS), it may be necessary to install it; for example,

    # yum install pam-devel.x86_64

    For details, refer to Using Pluggable Authentication Modules (PAM).

  • On some systems it will be necessary to update a configuration file, such as /etc/ldconfig.paths, and use ldconfig(8) (or equivalent) so that your system finds the correct shared libraries for the web server and programs that are executed by the web server, including the DACS web services. A command like ldd(1) or otool may be helpful.

  • Solaris and OpenSolaris are no longer supported. Notes regarding these unsupported platforms and deprecated releases of supported platforms may appear in the DACS documentation and source code.

  • DACS is not supported on Microsoft Windows platforms. Cygwin, which provides a GNU/Linux-like environment for Windows, is not an officially-supported platform, but earlier DACS releases would usually build on it. At that time, running DACS utilities and commands on Windows (such as dacscheck) required installing the binaries along with the Cygwin run-time libraries, such as /bin/cygwin1.dll and /bin/cygcrypt-0.dll.

Trying DACS

If at this time you only want to try DACS rather than doing a full install, review the information below regarding third-party packages and then proceed to follow the instructions you will find in dacs.quick(7), which is a step-by-step tutorial for installing and configuring DACS.

Upgrading DACS

If DACS 1.4 is already installed on your system and you are not changing any third-party packages or installation options, for a "quick and dirty" upgrade you can often install a new release on top of a previous release. While this will leave your existing DACS configuration files alone, it will also leave files that are no longer needed by the new DACS. Be sure to check the new distribution's release notes, HISTORY file, and the rest of this manual page for any notable changes and incompatibilities - you may need to make some adjustments to your pre-existing installation.

It is possible for minor, incompatible changes introduced by a new release to cause temporary, user-visible problems. For example, changes to the format of credentials might invalidate sessions (i.e., DACS HTTP cookies) issued by the earlier release, requiring users to reauthenticate.

  1. Make a backup copy of the previous install, just in case. It is especially important to make copies of all data files (such as DACS password files, other kinds of account files, encryption keys) and any custom configuration (such as access control rules).

  2. Obtain and unpack the new distribution and chdir to it;

  3. Review dacs.readme(7) and the instructions in this document;

  4. Copy src/config.nice from your installed version to the new src directory, make any updates and corrections that are necessary, and configure DACS:

    % cd src; sh ./config.nice

  5. Build DACS:

    % gmake

  6. We recommend that you remove some of the files from the previous release in case they are no longer required or have been renamed. Unless you have put non-standard files in them or made non-standard customizations, it is safe to simply delete these directories and their contents:

    % rm -f -r /usr/local/dacs/{acls,bin,include,lib,man,www}

  7. Stop httpd:

    % apachectl stop

  8. Install DACS:

    % gmake install

  9. Make and install the latest mod_auth_dacs module:

    % cd ../apache; gmake tag install

  10. Restart httpd:

    % apachectl start


    % apachectl startssl

  11. Check that DACS appears to be working correctly. You may find it handy to construct a set of links or bookmarks that you can use after installing or configuring DACS to invoke various DACS web services with appropriate arguments; for instance, try dacs_authenticate(8) dacs_current_credentials(8), dacs_prenv(8), dacs_list_jurisdictions(8), dacs_conf(8), dacs_signout(8), and dacs_version(8). Review the DACS log file for any error messages or warnings.

Installation Layout Overview

By default, DACS is installed under /usr/local/dacs. It is sometimes installed as /usr/local/dacs-version (e.g., /usr/local/dacs-1.4.51) with the current version symbolically linked to, and referenced as, /usr/local/dacs. In the documentation and DACS configuration files, the root directory used is referred to as DACS_HOME or the configuration variable ${Conf::DACS_HOME}. The locations of other components are usually specified relative to the actual root directory, as in site.conf (and its template, conf/site.conf-std) and dacs.conf. While the default layout of directories and files is adequate, system administrators often customize it, which is not difficult to do. Customization might be desirable for security, availability, aesthetic, or performance reasons.

Briefly, the default directory layout is as follows. The organization of files and directories within these directories can be customized by system administrators through changes to site.conf and dacs.conf and largely depends on how many federations and jurisdictions will be configured and how much configuration is shared by different federations and jurisdictions. Also see Configuration Variables.


The installation root directory.


Default access control list files for DACS web services and resources, copied from the distribution's acls directory.


This contains DACS commands and utilities (and excludes the mod_auth_dacs module, which is installed in Apache's modules directory).


Currently unused.


This directory will contain one directory per federation, and each of those subdirectories will contain one directory per jurisdiction. The following example shows a default configuration for a site that belongs to two federations, having domains fed1.example.com and fed2.example.com. The site has two jurisdictions (JUR1 and JUR2) at this site that belong to the former federation and one jurisdiction (JUR8) in the latter federation.




This directory contains header files for use with custom DACS code.


Run-time libraries are installed here.


Run-time log files are written here by dacs_acs(8) and DACS commands.


Analogous to /usr/sbin, system administrative commands are installed here.


DACS manual pages for use by man(1) are installed here.


Various temporary run-time files, such as lock files, are kept in this directory.


DACS HTML documentation is installed here.

Installing DACS

The following describes how to install DACS.


  • If another release of DACS is present, rename your previous release, install the new release, and then copy any site-specific configuration files from the previous release to the new release.

  • Be careful not to mix DACS binaries and support files from different releases. This can lead to strange behaviour that is often hard to resolve.

  • If you are installing or upgrading a third-party package, make sure that you are building it against the correct include files and libraries (e.g., ensure that the DACS build is not finding an old version, or using include files from one version and library files from a different version, or that httpd is trying to use the wrong version of an OpenSSL library). This is frequently the cause of build and run-time problems.

  1. Unpack the DACS distribution and move to its root directory.

  2. Familiarize yourself with the system by:

    • reading this document;

    • running:

      % src/configure --help

    • browsing through the documentation (best done by loading man/index.html into your browser);

    • deciding where you want the various components to be installed; and

    • considering which optional features you may want (you can easily make changes at any time, so do not be too concerned about this).

  3. A few third-party packages are required by DACS and must be built before DACS can be configured and built. Please note carefully if any special exceptions apply to your particular platform and third-party package needs. Although you may have better luck, sometimes we experienced problems building the recommended packages (or combinations of packages) on certain platforms; whenever possible, we try to provide a workable alternative. Late-breaking updates are sometimes available in the release's Post-Release Notes.


    It is not necessary to actually install these packages, you only have to build them so that the DACS build can use their libraries, include files, and so on, directly from where you build the packages. You may chose to do this if you do not want to upgrade an existing version of the package, or if you are unable to do so.

    Shared libraries belonging to these packages must be accessible at run-time, so please make sure that their path permissions enable them to be read by a program executing with Apache's CGI permissions.

    Build these packages in the order in which they are listed below.

    If you install a package, you may need to be root or use sudo(8) (e.g., "sudo make install").

    These packages are not distributed with DACS and have licensing terms completely separate from those of DACS that are your responsibility.

    1. Install the Expat XML parser

      This release of DACS has been tested with Expat 2.6.2 and we recommend that you use that release.

      For use with DACS, Expat can either be built with -prefix=/usr/local or something like -prefix=/usr/local/expat-2.6.2, whichever you prefer. In the former case, you can omit the --with-expat when configuring DACS or use --with-expat=/usr/local, and in the latter case you must use --with-expat=/usr/local/expat-2.6.2. After Expat has been unpacked, we currently build Expat using the more recent cmake method:

      % cd expat-2.6.2
      % mkdir build && cd build
      % cmake -DCMAKE_INSTALL_PREFIX=/usr/local/expat-2.6.2 ../
      % make
      (All should go well.)
      % make test
      (All should go well.)
      % make install
      (All should go well here, too.)

      Alternatively, if cmake is unavailable, from the Expat distribution's source directory (possibly called expat) and, if necessary, after creating the configure script by running ./buildconf.sh):

      % cd expat-2.6.2
      % ./configure --prefix=/usr/local/expat-2.6.2
      % make
      (All should go well.)
      % make install
      (All should go well here, too.)


      On Win2K/Cygwin, only a static library is needed. From the root of the expat distribution directory:

      % cd lib; ar rv libexpat.a *.o; ranlib libexpat.a

      If the build fails, reconfigure using --enable-shared=no and --enable-static=yes and try to build it again.

    2. Install OpenSSL

      DACS requires cryptographic functionality provided by OpenSSL. This release of DACS has been tested with openssl-3.2.2 and we recommend that you use that release with DACS. Although the OpenSSL Project recommends that the 1.1.1 branch not be used, OpenSSL 1.1.1w and later should still work with DACS. Apache should be built using the version of OpenSSL recommended by the particular Apache release - using a more recent version of OpenSSL may introduce build problems or run-time bugs in Apache. It is not necessary for Apache and DACS to use the same release of OpenSSL.


      • DACS will likely build and operate with other (recent) releases of OpenSSL, but they may have important security issues and they are not officially supported with this version of DACS.

      • Starting with DACS 1.4.50, DACS will build with OpenSSL 3.2, which is the recommended branch. Note that DACS and any third-party libraries that it is built with must use the same version of OpenSSL.

      • If you are enabling DACS support for Java, add the -fPIC flag to config when you are building OpenSSL.

      • In some configurations you may want or require shared OpenSSL libraries; if so, add the shared command line flag to config when building OpenSSL.

      • Here is how we usually build OpenSSL:

        % ./config --prefix=/usr/local/openssl-3.2.2 --openssldir=/usr/local/openssl-3.2.2 \
            -fPIC shared "-Wl,-rpath,/usr/local/openssl-3.2.2/lib"

      • On CentOS, the OpenSSL build procedure may install its libraries in lib64 rather than lib (a relatively recent, unwelcome change). In that case you would need to use "lib64" instead of "lib" when running configure and whenever building other packages (such as OpenLDAP) that need the library path. The example above would use "-Wl,-rpath /usr/local/openssl-3.2.2/lib64". (Alternatively: make a symbolic link so that both directory names exist.)

        If you see the error message "Can't locate IPC/Cmd.pm in @INC ..." when building on Centos, try again after doing:

        % yum install perl-IPC-Cmd

      • On macOS it is sometimes necessary to explicitly request a 64-bit build of OpenSSL:

        % ./Configure darwin64-arm64-cc --prefix=/usr/local/openssl-3.2.2 \
            --openssldir=/usr/local/openssl-3.2.2 -fPIC shared

      Before the switch to the arm64 architecture, the first argument above was darwin64-x86_64-cc.

    3. Install Apache 2.4.59

      You will need an SSL/TLS-capable Apache server (build Apache with --enable-ssl) that uses a recent version of OpenSSL (build Apache using --with-ssl=path, see above).


      The Apache HTTP Server Project has announced that it has discontinued all development and patch review of the 2.2.x series of releases, with 2.2.34 being the final release. It strongly encourages users to promptly complete their transitions to the 2.4.x branch of httpd to benefit from security and bug fixes, and new features.

      DACS 1.4.40 was the final version to officially support the Apache 2.2 series. Subsequent releases of DACS are not maintained, tested, or documented with Apache 2.2 series servers.


      You can install a subset of DACS that does not require Apache and does not require any DACS configuration. These stand-alone, general-purpose utility commands, such as dacshttp and sslclient, might be of interest to you even if you are not interested in any other parts of DACS. Look for BASIC_PROGS in Makefile.in to see which commands will be installed.

      To build this subset, use --with-apache=omit when running configure. Please continue to review the information about third-party packages in this document, but you can ignore anything that follows that is related to Apache and mod_auth_dacs.

      If you want to use mod_auth_dacs as a dynamic module, which is the recommended configuration, make sure that mod_so is built-in to your httpd ("httpd -l" displays a list).


      • This release of DACS has been tested with Apache 2.4.59.

      • Detailed instructions for building Apache 2.4.59 can be found in Apache's INSTALL file. For the testing platforms, we get the APR and APR-UTIL libraries from apr.apache.org and unpack them in the Apache distribution's srclib directory, then rename them srclib/apr and srclib/apr-util, respectively, as it says in INSTALL. We currently use apr-1.7.4 and apr-util-1.6.3. If you are building httpd this way, include the --with-included-apr flag with configure, such as:

        # ./configure --prefix=/usr/local/apache2-2.4.59 --enable-ssl=static \
            --with-ssl=/usr/local/openssl-3.2.2 --with-included-apr \
            LDFLAGS="-L/usr/local/openssl-3.2.2/lib -Wl,-rpath,/usr/local/openssl-3.2.2/lib"

      • On CentOS 5.9 and later, the Apache build may fail with a complaint about not finding pcre-config. To solve this, try:

        # yum install pcre-devel.x86_64

      • If suitable APR, APR-UTIL, and other support libraries have already been installed on your system, you may be able to perform a basic build and install of Apache 2.4 with a command like:

        % cd httpd-2.4.59
        % ./configure --prefix=/usr/local/apache2-2.4.59 --enable-ssl \
        % make install

      • We sometimes run into minor problems configuring or building Apache 2.4 on macOS, especially after a recent Xcode upgrade. Ensure your PATH is correct. It is sometimes necessary to make a symbolic link from an Xcode directory /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/... to a more conventional path so that it is found.

        If necessary, obtain Perl Compatible Regular Expressions (PCRE) from https://pcre.org and install it, then make sure that pcre-config is on your PATH. Use the pcre library, not pcre2.

        Recent builds of APR and/or httpd on macOS (macOS 14.4, arm64, Xcode 15.3, Apache 2.4.59) have failed because configure failed to find various symbols (Example: "error: Can not determine the proper size for pid_t"). The problem appears to be that capability probing programs generated by configure, most of which call exit(3), must include stdlib.h. A fix: from the root of the Apache distribution, edit ./configure and ./srclib/apr/configure and ensure that every generated test program has an #include <stdlib.h> (look for #include <stdio.h> or #include <sys/types.h> and insert the line). Then rerun configure and "make clean; make".

      • If you decide not to use the APR and APR-UTIL libraries that ship with Apache, remove or rename the existing directories and install the fresh copies, which is the procedure we usually follow. Currently, these are apr-1.7.4 (APR) and apr-util-1.6.3 (APR-UTIL). After unpacking fresh copies of APR (as srclib/apr) and APR-UTIL (as srclib/apr-util), configure, build, and install them. We then build httpd using the --with-apr and --with-apr-util flags. When you build DACS in an upcoming step, you will probably need to use the --with-apache and --with-apache-apr flags (see Third-party support options). If you are going to use the --with-berkeley-db flag when building APR-UTIL (e.g., --with-berkeley-db=/usr/local/BerkeleyDB.5.3), you may want to temporarily skip ahead to build Berkeley DB before returning here to continue your Apache build. (Note: apr-util will sometimes not work with the latest versions of Berkeley DB; refer to documentation for its --with-dbm flag).

        Because we deal with multiple versions of third-party packages, each release is installed separately, hence the version numbers in the pathnames.

        If you encounter problems building dacsversion, it may be necessary for you to go back and build APR with the --disable-lfs flag to disable large file support on your platform.

        On FreeBSD, when doing the top level Apache configuration above it was necessary to add "-rpath /usr/local/db-5.3.28/lib -rpath /usr/local/openssl-3.2.2/lib" to LDFLAGS so that Apache commands could find shared libraries at run time.

        On CentOS, when building apr-util, and at the top level, it was necessary to use (instead of the -rpath flags) "-Wl,-rpath /usr/local/db-5.3.28/lib -Wl,-rpath /usr/local/openssl-3.2.2/lib" to LDFLAGS.

        Alternatively, on either platform the ldconfig command or LD_LIBRARY_PATH might be used. It appears that the LDFLAGS above should be omitted on macOS.

      • In some configurations an "undefined ssl_hook_Fixup symbol", "Undefined symbol 'ssl_hook_Fixup'", or "Cannot load modules/mod_ssl.so into server" error is produced by httpd when it starts up. This was also seen in earlier releases of Apache. These errors can be due to an apparent bug in the Apache build procedure that results in the mod_ssl module not knowing where libssl.so and libcrypto.so are, even though the correct path was specified at Apache build time through the --with-ssl flag to configure.

        One solution is to make mod_ssl a built-in module instead of a dynamically loaded module. Build Apache using something similar to this (using the --enable-ssl=static flag is the important change):

        % ./configure --prefix=/usr/local/apache2-2.4.59 \
            --with-ssl=/usr/local/openssl-3.2.2 --enable-ssl=static

        Then do a "make install". Note that you will need to comment out the httpd.conf directive that loads mod_ssl:

        # LoadModule ssl_module modules/mod_ssl.so

        Now, from the Apache installation directory, try:

        % bin/httpd -l
        % bin/httpd -M

        If httpd cannot find your OpenSSL libraries, you will see an error message like this:

        error while loading shared libraries: libssl.so.1.0.0: cannot open
          shared object file: No such file or directory

        Tell the linker where the OpenSSL libraries are by setting the LD_LIBRARY_PATH environment variable for httpd; for example:

        %  sh -c "export LD_LIBRARY_PATH=/usr/local/openssl-3.2.2/lib; bin/httpd -M"

        You may also be able to resolve the problem using the ldconfig command, but we don't know if that could possibly break other programs that expect a different version of the OpenSSL library. You will need to always set LD_LIBRARY_PATH before running httpd, maybe using an alias or script. If you use apachectl to manage Apache, you could simply have it set LD_LIBRARY_PATH (also see the Apache envvars script, which is sourced by apachectl).

        Another thing to try if Apache is unable to load a shared library is to re-run configure without the --with-dbm flag.

      • Sometimes the Apache build procedure insists on using the system's version of apr or apr-util rather than the version you explicitly asked configure to use with --with-included-apr, --with-apr, or --with-apr-util (check using: ldd bin/httpd or otool bin/httpd). If the linker complains about an undefined symbol when you attempt to start Apache, it may be linking against an incompatible (and older) Apache portable runtime library. Hiding the apr-1-config (apu-1-config) command has not proved effective. The easiest solution we have found is to hide (rename) the libapr* system libraries that you don't want configure to use and then re-configure and re-make Apache, checking that the installed httpd is now referencing the expected libraries. Revert the names of the system libraries you changed if you think it might be necessary to use them.

      • If you find that your Apache server on CentOS does not accept requests coming from the network (non-localhost requests) it may be because the operating system's security policy is disallowing them. As root, do:

        # system-config-firewall

        (This command is sometimes named system-config-securitylevel, or system-config-firewall-tui in various releases of CentOS). In the "Other ports" section of the "Firewall Options", add the HTTP/HTTPS port(s) you want to use for protocol TCP. Once the change is applied it is persistent. Another option, if it is safe to do so, is to totally disable the firewall. On CentOS:

        # service iptables stop

        (Alternative: systemctl disable firewalld) Note that this change is not persistent, however. Another alternative, for CentOS and other systems, is to use the appropriate command (e.g., iptables, ipfw, or pfctl) to add a firewall rule to allow TCP access to your HTTP/HTTPS port(s).

      • One difference to be aware of between the Apache 2.0 branch and subsequent branches is that the default Apache configuration of the newer branches may deny all access by default; some DACS files should be publicly accessible, however, so you may need to explicitly allow this. For example, in httpd.conf:

        <Directory /usr/local/dacs/www>
          Satisfy Any
          Allow from all
          Options Indexes FollowSymLinks

      • Apache 1.3 is not supported; please consult the FAQ. DACS has not been tested with Apache 2.3 or 2.4.

      • We do not support using mod_auth_dacs with a non-source install of Apache; we have received feedback that it can be done manually without much effort, however. In this case, we believe that the install may go more smoothly if you use the configure flag --disable-shared.


      Check that Apache is working properly and that it is actually using the version of OpenSSL that you are expecting. It is important to confirm that your server is working correctly with your web resources before DACS gets involved. Doing so can save you time and frustration.

      You can see your httpd's Server response-header by connecting to your server (e.g., using telnet) and engaging in an interaction with it similar to the following (note the last line of output):

      % telnet localhost 80
      Connected to localhost.
      Escape character is '^]'.
      GET / HTTP/1.0
      HTTP/1.1 200 OK
      Date: Tue, 17 Sep 2019 18:08:11 GMT
      Server: Apache/2.4.41 (Unix) OpenSSL/1.1.1d mod_auth_dacs/1.4.40(Release date 31-Aug-2018 09:49:34) PHP/5.6.14

  4. A few third-party packages are optional and whether you need them depends on which optional features of DACS you require. These packages must be built before DACS can be configured and built. If you decide you want to add or remove optional capabilities after building DACS, it is easy to do so later.


    If you are new to DACS, it may be a good idea to first build it without any optional packages. After you have gotten the basic system working to your satisfaction, rebuild DACS with the optional components you need. Or, if you are not sure at this time which optional packages you need, return to this step later.

    1. Berkeley DB, gdbm, ndbm DB (dbm-type databases)

      If you want to be able to store DACS configuration information in a database or need to access files managed by Apache's mod_auth_dbm, you may use Berkeley DB from Oracle Corporation (Sleepy Cat Software was acquired by Oracle in February, 2006). A suitable version may already be installed on your system. Typically, Apache will only build with a version of Berkeley DB that is somewhat older than the latest. Neither DACS nor Apache require Berkeley DB, and they do not need to use the same version of Berkeley DB. Version db-5.3.28 is being used for testing, but somewhat older versions should be fine. See the DACS configure arguments: --enable-bdb, --disable-bdb, and --with-bdb.


      Note that starting with db-6.x, licensing for Berkeley DB changed from the Sleepycat License to the GNU AGPL v3. Installations should consider whether they should use db-5.3.28 or switch to another supported dbm-type database.


      You may find that you must sign on to the Oracle site before you are allowed to download Berkeley DB. You may be able to avoid this by using a URL such as:


      You may also be able to obtain Berkeley DB elsewhere, such as at linux.softpedia.com, pkgs.fedoraproject.org, or fossies.org. Consider validating the downloaded file using a checksum published on a different site, however.

      The default is to use Berkeley DB if it is available. If you do not want to use Berkeley DB you must disable it (--disable-bdb). Similar functionality is provided by the NDBM library and from GNU GDBM (versions 1.8.3 through 1.23, the latter being the version tested against). GNU GDBM must be built with its NDBM compatibility mode. These libraries may already be installed on your system. Get GDBM from http://ftp.gnu.org/gnu/gdbm. See the --enable-ndbm, --with-gdbm-lib, and --with-gdbm-includes configure flags.


      • It may be necessary to create (or update) links to the Berkeley DB installation directory to avoid problems when building other packages. For example, if you install it in /usr/local/db-5.3.28:

        % ln -sf /usr/local/db-5.3.28 /usr/local/BerkeleyDB.5.3
        % ln -sf /usr/local/db-5.3.28 /usr/local/db53

      • Here is how we built Berkeley DB for DACS after unpacking it:

        % cd build_unix
        % ../dist/configure --prefix=/usr/local/db-5.3.28 CFLAGS=-fPIC
        % make
        (All should go well.)
        % make install
        (All should go well here, too.)

      • On some platforms (macOS) there may be a compilation error regarding the redefinition of __atomic_compare_exchange in src/dbinc/atomic.h. Change the two instances of that function name in that file to anything unique (e.g., __dacs_atomic_compare_exchange).

      • On some platforms, applications (including DACS) that use Berkeley DB may need to be linked with the -lpthread flag.

      • Here is how we built GDBM for DACS after unpacking it:

        % ./configure --prefix=/usr/local/gdbm-1.23 --enable-libgdbm-compat
        % make
        (All should go well.)
        % make install
        (All should go well here, too.)

      • You cannot enable the NDBM library and GNU GDBM. You can use either one with Berkeley DB.

      • GNU GDBM 1.9.1 and newer may not interoperate correctly with databases created by older versions of GNU GDBM; consult its source code and documentation for details.

      • A deficiency in configuration processing is that the location of the NDBM library cannot be specified; the standard configuration search path is used. A future version should provide a --with-ndbm flag.

      • The NDBM-workalike, sdbm, is not currently supported. It may be added to a future release if it is requested.

    2. SQLite

      The SQLite database, which can be used together with the dbm-type databases, is another option for storing DACS configuration information. Version 3.46.0 is being used for testing (we use the "sqlite-autoconf" amalgamation tarball). See the DACS configure arguments: --enable-sqlite, --disable-sqlite, and --with-sqlite.


      • Here is how we built SQlite:

        % ./configure --prefix=/usr/local/sqlite-3.46.0
        % make
        % make install

      • On FreeBSD at least, an apparent bug in the SQlite build procedure can cause a compilation error. To avoid the error, after running configure edit the definition of the DEFS symbol in the Makefile to remove the embedded space by changing:

          -DPACKAGE_STRING=\"sqlite 3.46.0\"



    3. libdsm

      If you want to be able to authenticate using Microsoft's SMB/NTLM protocol (see local_ntlm_authenticate), you must configure DACS to use the custom implementation of the libdsm library that ships with DACS.


      For a very long time, Samba (specifically, Samba 3.x), a Microsoft Windows interoperability suite, was the only option for providing NTLM client authentication for DACS. But because Samba 3.x has not been supported by the Samba team for a long time, and Samba 4.x has proved to be difficult to build on DACS platforms and is not a drop-in replacement for Samba 3.x in any case, the smaller and simpler libdsm has replaced Samba.

      Samba 3.x may still be used by this version of DACS but support for Samba is deprecated, no longer tested, and will be removed.

      DACS NTLM authentication using libdsm is currently tested against services provided by Windows Server 2012 but DACS should also interoperate with other MS Windows platforms.

      libdsm Notes

      Although the library is currently functional and tested, configuration of libdsm is still not fully integrated within the main DACS build. To use libdsm:

      1. Unpack the DACS tarfile

      2. chdir to dacs-1.4.51/src/libdsm and refer to the README in that directory for up-to-date, detailed instructions.

        We continue here with a brief outline of the procedure to build the library. If you are going to enable NTLM authentication, or think you might do so later, build the library before running configure for DACS. If you do not need NTLM authentication, you need not build the library.

      3. Obtain the GNU libraries libtasn1 (libtasn1-4.19.0) and libiconv (libiconv-1.17). No changes to those libraries are required. Build both libraries in place. If the latest versions are unavailable, any fairly recent versions of these libraries should be fine provided no security issues have been announced.

      4. Configure and make the modified libdsm. The library is installed in its root directory and no system files or directories are modified. A program called ntlmauth will be built. You should use it to test authentication against your Windows server.

      5. If all goes well, build DACS as you normally would, except instead of configuring it using




        Test authentication again, this time using dacsauth (refer to dacsauth(1) and local_ntlm_authenticate for examples).

      6. If you are satisfied with the results of your testing, complete your installation of DACS and verify that dacs_authenticate also works correctly. The only change you may need to make to dacs.conf is to specify

        OPTION 'SAMBA_PORT="0"'

        in the appropriate Auth clause. If you are using the standard ports, you may delete that option entirely since the library knows which port(s) to try.

      7. Please report any problems so that they can be addressed in the next release.

      Historical Samba Notes

      • Samba support is now deprecated. If you use choose to use Samba regardless, the last version of Samba that functioned with DACS was samba-3.6.25.

        The following notes are carried over from the last release of DACS that officially operated with support from Samba:

      • DACS requires the Samba source distribution to be built but it does not matter if Samba is installed. The DACS build procedure looks for include files and libraries relative to the Samba distribution's root directory.

      • On systems where libexecinfo has been installed (FreeBSD), when building DACS it may be necessary to add -lexecinfo to LDFLAGS if backtrace or backtrace_symbols are referenced by Samba.

      • The Samba 4.X releases use a different build system than earlier releases, unfortunately. DACS does not currently work with the 4.X releases, mainly because we have had no success getting a clean build of any 4.X release on either FreeBSD or macOS.

      • To build Samba for DACS, from your Samba distribution's ./source3 directory do:

        % ./configure --enable-static=yes --with-ads=no --with-ldap=no --disable-swat --disable-cups --disable-pie \
              --enable-external-libtalloc=no --enable-external-libtdb=no
        % make

      • Then, when configuring DACS, specify the directory where Samba was unpacked, for example:


      See the DACS configure arguments: --enable-ntlm-auth, --with-samba, and --with-libdsm.

    4. libxml2 and xmlsec1

      InfoCard support is now deprecated and therefore these libraries are no longer needed. This section may be removed in a future release.

      See local_infocard_authenticate.

      InfoCard support requires libxml2 and xmlsec1 are required. Build libxml2 and OpenSSL first, because xmlsec1 depends on both of them. This release of DACS has been tested with libxml2-2.8.0 or libxml2-2.9.1, and xmlsec1-1.2.20, and we strongly recommend that you use those versions. It is not known whether this release of DACS will work with any other versions - we do not officially support them.


      • Here is how we built libxml2:

        % ./configure --prefix=/usr/local/libxml2-2.9.1

        Due to an apparent bug in the code (in threads.c) that results in a syntax error, it was necessary to add --with-threads=no on some platforms, such as macOS.

      • Here is how we built xmlsec1:

        % ./configure --prefix=/usr/local/xmlsec1-1.2.20
            --with-openssl=/usr/local/openssl-1.0.2p --with-gnu-ld
            --enable-static-linking  --disable-crypto-dl --disable-apps-crypto-dl 

        Except on macOS:

        % ./configure --prefix=/usr/local/xmlsec1-1.2.20 \
              --with-libxml=/usr/local/libxml2-2.9.1 --with-gnu-ld --enable-static=yes \
              --enable-shared=yes --with-nss=/Applications/Firefox.app/Contents/MacOS \
              --with-nspr=/Applications/Firefox.app/Contents/MacOS \
              --with-openssl=/usr/local/openssl-1.0.2p \

      • Due to an apparent error in its build procedure, we sometimes encountered the following error message:

        *** Warning: Linking the shared library libxmlsec1-openssl.la against the
        *** static library /local/openssl-1.0.2p/lib/libcrypto.a is not portable!

        After ensuring that libcrypto.so (or libcrypto.dylib) had been installed when building OpenSSL, to correct the xmlsec1 build problem we did "make clean", re-ran configure as above, and edited src/openssl/Makefile under the root of the xmlsec1 distribution directory to change all occurrences of "libcrypto.a" to "libcrypto.so". It was sometimes also necessary to delete the -ldl flag on those same lines, and in other Makefile files in the distribution (and making sure the flag was not specified by xmlsec1-config). After those changes, we ran make again. Additionally, it was sometimes necessary to specify CFLAGS="-I/usr/local/include -L/usr/local/lib".

      • Another problem related to this library on a CentOS platform resulted in an error message similar to this:

        Cannot restore segment prot after reloc: Permission denied

        The solution was to issue the command (adjust the path as necessary):

        % chcon -t texrel_shlib_t /usr/local/xmlsec1-1.2.20/lib/libxmlsec1-openssl.so

      • When including InfoCard support on macOS, it was necessary to tell the dynamic linker where to find the xmlsec1 library (despite using the -rpath flag during the build). To work around this, do something like the following (or equivalent):

        % setenv DYLD_LIBRARY_PATH /usr/local/xmlsec1-1.2.20/lib

        Ensure that "gmake test" does not fail.

      • Due to an apparent bug in configure.in, on FreeBSD configure may incorrectly use the -ldl flag in generated Makefiles. Either edit all Makefiles to remove all occurrences of the -ldl flag, or edit configure.in, add a "*-*-freebsd*" case like the others in the "OpenSSL" section, run autoconf to regenerate configure, and then "make clean" and re-run configure.

      • Your experience may differ, but we found xmlsec1 to not cooperate when we wanted to work with multiple installations of libxml2 - apparently if a libxml2 directory or link has been installed, its build procedure seems to use that version, regardless of what is specified on the command line, requiring manual editing of its Makefiles. Check that the correct instance of xml2-config is being used. Unfortunately, it may be necessary to remove (or temporarily rename) older installed versions, or fall back to using an older version already installed on your system.

      • We also found it sometimes necessary to also upgrade the version of the libxslt library (also available here) to build against the same libxml2 as xmlsec1 library, otherwise multiple versions of libxml2 may be referenced, leading to undefined symbols during the DACS build procedure. We have had success using libxslt-1.1.28 (and then adding --with-libxslt=/usr/local/libxslt-1.1.28 when configuring libxslt).

      The DACS build procedure uses xmlsec1-config, a program that comes with xmlsec1. If InfoCard support is enabled, the build procedure will look in some standard places for this command. You can specify its location with the --with-xmlsec1-config flag.

      See the DACS configure arguments: --enable-infocard-auth and --with-xmlsec1-config

    5. OpenLDAP

      Authentication through LDAP or Microsoft Active Directory (see local_ldap_authenticate) is implemented using OpenLDAP. This release of DACS has been tested only with openldap-2.6.8 and we strongly recommend that you use that version.

      It is not known whether this release of DACS will work with any other version of OpenLDAP - we do not support them. DACS may work properly with OpenLDAP versions at least as old as 2.2.24, if you really must use one of them.

      DACS LDAP authentication and role retrieval is currently tested against directory services provided by Windows Server 2012 but DACS should also interoperate with other LDAP implementations.

      If the --with-ldap flag is not given (in which case LDAP authentication must be enabled; e.g., via --enable-ldap-auth), configure will search for OpenLDAP headers and libraries; if found, it will assume they are a suitable version and use them.

      If --with-ldap is given (either because OpenLDAP is not installed or an unsuitable version is installed), headers and libraries relative to the root of the specified directory will be used rather than any installed OpenLDAP files; it is not necessary to install OpenLDAP, you only need to build it - so you do not need to be concerned about hassles associated with upgrading or any other versions that might already be installed on your system.

      To build OpenLDAP for DACS, from the root of your OpenLDAP distribution do:

      % ./configure --with-tls=openssl --disable-slapd --enable-static \
          CPPFLAGS="-I/usr/local/openssl-3.2.2/include" \
          LDFLAGS="-L/usr/local/openssl-3.2.2/lib -Wl,-rpath,/usr/local/openssl-3.2.2/lib"
      % make

      If configure fails, try using CFLAGS instead of CPPFLAGS above. If requested, do a "make depend" before the make.

      See the DACS configure arguments: --enable-ldap-auth and --with-ldap

    6. Readline

      The history and editing functionality provided by the GNU Readline Library is entirely optional but can be nice to have when using dacsexpr(1) interactively. This release of DACS has been tested with version 8.2, although we have used readline-6.X with recent releases of DACS. Note that you may need to compile Readline with the -fPIC flag ("make CFLAGS=-fPIC"). Current and previous source code releases are available.

      It is not necessary for you to install readline, you only need to build it - so you do not need to be concerned about hassles associated with upgrading or any other versions that might already be installed on your system. If readline/readline.h is in a standard include directory, it has probably been installed and no action is necessary. On platforms where it is missing, it may be simple to install using a command such as:

      # yum install readline-devel.x86_64


      # pkg install readline


      • When building on macOS, it was sometimes necessary to fix a bug by editing shlib/Makefile and making this change:

        #SHOBJ_LDFLAGS = -dynamic
        SHOBJ_LDFLAGS = -dynamiclib

      See the DACS configure arguments: --with-readline

  5. Configure and build DACS libraries, services, commands, and utilities

    See Build Options for build alternatives and options to configure.

    % cd src
    % ./configure
    % gmake


    • Consider installing DACS in a version-named directory, then updating a symbolic link to it after testing is successful. This makes it simpler to revert to a previously installed version.

      % ./configure --prefix=/usr/local/dacs-1.4.51 ...
      % ln -f -s /usr/local/dacs-1.4.51 /usr/local/dacs

    • When building on macOS it may be necessary to provide a target specification to configure:

      % ./configure --build=arm64-apple-darwin ...

    To confirm that DACS has been built with the third-party packages that you intended, from the src directory run:

    % ./version -v

    You should ensure that the sslclient utility is working correctly. From the src directory, you can test it using the following command:

    % printf "GET https://dacs.dss.ca:8443 HTTP/1.0\r\n\r\n" | ./sslclient dacs.dss.ca:443

    which should print the contents of https://dacs.dss.ca to the standard output. You should repeat this test substituting the name of your server and port.


    After building DACS, it is strongly recommended that you run the self-tests (expression evaluation, crypto code, string handling, and so on) from the src directory:

    % gmake test

    If any error occurs during testing, testing will stop immediately and a message will be displayed. In this event, first check that you are using the recommended software packages and that your build flags are correct. Most often, problems are the result of mixing header files or library files from different versions of a third-party package (e.g., OpenSSL) or incorrect file permissions. If you cannot find anything wrong with your configuration, please submit a bug report that includes the self test output and describes your platform (you can include the output of "./version -v").

  6. If all looks good, install DACS

    % gmake install


    • If gmake complains about not being able to find xsltproc, docbook.xsl, or something that might be related to installing the documentation, try:

      % (cd ../man; gmake touch)
      % gmake install

    • This will install the rules for the standard DACS web services and run dacsacl(1) to create and install an index for them.

    • You can specify DESTDIR to gmake when installing or uninstalling:

      % gmake DESTDIR=/tmp/mydacs install

    The installation process may prompt you for the owner name and group name to use for files and directories; it will guess at reasonable defaults for your platform. The appropriate responses will depend on local conventions, but to start with you might set the owner to your login name or root, and the group name to the same name that is used by Apache (specified by the Group directive in httpd.conf). For the group, it may help to look at /etc/group. If you need to change your owner or group selection, remove src/.ownername or src/.groupname and try again.


    While running "gmake install", important instructions regarding manual installation steps may be displayed. A copy is written to .build_notes, truncating any previous contents.

  7. As part of the installation procedure, the DACS manual pages are copied into the DACS man directory (default: /usr/local/dacs/man). If you adjust your MANPATH environment variable to include that directory, try:

    % man dacs

    While it is occasionally handy to view the manual pages using the man command, the HTML documentation is far superior.

  8. Build a DACS-enabled httpd

    Please consult apache/README in the DACS distribution for details and, from the apache directory, do:

    % gmake help


    You can build the mod_auth_dacs module with a module identification string (a "version tag") with varying amounts of detail, or without a tag. For a full-length tag, use "gmake tag", for a simple tag use "gmake smalltag", or to disable the tag use "gmake notag" or "gmake module". We suggest that you compile mod_auth_dacs with a tag so that Apache's SERVER_SIGNATURE and Server response header field can include DACS version identification; this makes it easy to tell which version of DACS the server is running and helps to detect mismatches. If mod_auth_dacs is compiled with debugging enabled or if the SetDACSAuthDebug directive enables debugging, additional version information is added to the tag. For production use, identifying the modules in your Apache server is considered by some to be a potential security weakness - you may reasonably choose not to include the version tag. For some versions of Apache, module identification can be suppressed at runtime through its ServerTokens directive.

    If you want mod_auth_dacs to be a dynamic module, which is recommended, do:

    % cd apache
    % gmake tag
    % gmake install

    Check that your httpd.conf has the appropriate LoadModule directive.


    When installing mod_auth_dacs on some platforms (such as FreeBSD 10.0), messages similar to the following may be seen:

    Warning!  dlname not found in /usr/local/apache2.4/modules/mod_auth_dacs.la.
    Assuming installing a .so rather than a libtool archive.
    chmod 755 /usr/local/apache2.4/modules/mod_auth_dacs.so
    chmod: /usr/local/apache2.4/modules/mod_auth_dacs.so: No such file or directory
    apxs:Error: Command failed with rc=65536

    In this situation you should notice that a shared library (a .so file) has not been created in the Apache modules directory. This problem is apparently caused by a buggy version of libtool that ships with Apache (e.g., /usr/local/apache2.4/apr-httpd/build-1/libtool) and is invoked by apxs by gmake install. To work around this issue, edit the apxs command that is run from the Makefile in the DACS apache directory (e.g., /usr/local/apache2.4/bin/apxs). Modify the apxs script to execute the system's libtool instead of Apache's. This change will suffice, for example:

    #my $libtool = `$apr_config --apr-libtool`;
    my $libtool = "/usr/local/bin/libtool";

    After the change, repeat the gmake install. If this fails with the error message:

    libtool: compile: unable to infer tagged configuration


    my $libtool = "/usr/local/bin/libtool --tag=CC";

    If you want mod_auth_dacs module to be a static module:

    1. Copy apache/mod_auth_dacs.c to Apache's modules/aaa directory

    2. Re-run Apache's configure, adding mod_auth_dacs (--with-module=aaa:auth_dacs)

    3. Reinstall Apache:

      % make install

    4. Verify that mod_auth_dacs appears in the list of Apache modules:

      % httpd -l


    Because mod_auth_dacs references symbols in mod_ssl, apparently those symbols must be loaded before mod_auth_dacs is loaded. This can be ensured by statically compiling mod_ssl into httpd (configure httpd with --enable-ssl and verify with "httpd -l") and using the following directive in httpd.conf to dynamically load the mod_auth_dacs module:

    LoadModule auth_dacs_module modules/mod_auth_dacs.so

    Alternatively, it may be sufficient to dynamically load mod_ssl before mod_auth_dacs.

    If mod_ssl symbols are unavailable when they are needed, you'll probably see a message like the following when you try to start httpd:

    mod_auth_dacs.so: undefined symbol: ssl_hook_Fixup

    After you've installed mod_auth_dacs, restart httpd.

    If you built the module with a tag, verify that the DACS version identifier appears in SERVER_SIGNATURE. You can do this by hitting Apache's printenv CGI program from your browser or using a command like:

    % dacshttp "http://myserver:myserverport/cgi-bin/printenv"

    (first making sure that Apache's printenv CGI is executable) and examining the SERVER_SIGNATURE environment variable, or by running:

    % telnet myserver myserverport

    and typing:

    OPTIONS * HTTP/1.0

    followed by a blank line and examining the Server response header.


    • The URLs that follow will use http and omit myserverport. Substitute https and/or include myserverport as necessary for your configuration.

    • If you install a new version of DACS, please make sure that you use the mod_auth_dacs module that comes with it. Follow the instructions above.

  9. An assortment of DACS files, including HTML documentation and CSS files, are copied into the DACS www directory (default: /usr/local/dacs/www).

    While you can view the documentation simply by pointing your web browser at the DACS www directory, it is recommended that you make it available through Apache using its Alias directive because the default site configuration (site.conf-std) expects handlers and DTDs to be available using certain URLs.

    Add lines like the following to your httpd.conf:

    Alias /dacs      "/usr/local/dacs/www/"
    Alias /css       "/usr/local/dacs/www/css/"
    Alias /dtd-xsd   "/usr/local/dacs/www/dtd-xsd/"
    Alias /examples  "/usr/local/dacs/www/examples/"
    Alias /handlers  "/usr/local/dacs/www/handlers/"
    Alias /infocards "/usr/local/dacs/www/infocards/"
    Alias /man       "/usr/local/dacs/www/man/"
    Alias /misc      "/usr/local/dacs/www/misc/"
    Alias /mod       "/usr/local/dacs/www/mod/"

    To see the DACS DTD files from your browser, you can also add:

    AddType text/plain      .dtd

    These .dtd files are only used to document XML structures and messages used by DACS and are cited in the documentation.

    You should also uncomment these two directives in your site.conf file:

    XSD_BASE_URL "/dacs/dtd-xsd"
    DTD_BASE_URL "/dacs/dtd-xsd"


    After restarting httpd, you can view the documentation using a URL that looks like http://myserver/dacs/man or simply http://myserver/man.

  10. Access to all DACS web services (everything installed in the .../cgi-bin/dacs directory) must be controlled by DACS; that is, they must be "DACS-wrapped". Assuming you are following the defaults for installing DACS, these are the only files that are required to be DACS-wrapped.

    DACS-wrapping a resource or set of related resources involves:

    • Configuring Apache so that it uses DACS to manage access to the contents of a directory or portion of URL space and

    • Configuring one or more DACS access control rules for the jurisdiction responsible for the resources (this is done for the DACS web services by the default ACLs).

    Configuring Apache involves, at minimum, adding directives like the following to the appropriate VirtualHost section of httpd.conf:

    AddDACSAuth dacs-acs /usr/local/dacs/bin/dacs_acs "-t -v"
    SetDACSAuthMethod dacs-acs external
    SetDACSAuthConf dacs-acs "/usr/local/dacs/dacs.conf"
    <Location /cgi-bin/dacs>
       AuthType DACS
       AuthDACS dacs-acs
       Require valid-user
    # Note: For Apache 2.4, instead use:
    # Require dacs-authz
       Options ExecCGI


    Remember to restart Apache after making changes to httpd.conf.

    Some administrators may choose to make all content or all CGIs DACS-wrapped. That is probably a more secure approach, although of course it can be somewhat less efficient than segmenting the server's URL space into "secure" and "insecure" areas. Content that is not DACS-wrapped is totally oblivious to DACS and incurs no overhead due to DACS. Also, this approach may necessitate making "holes" in the URL space for non-access controlled resources, which must be done with care.


    If you decide to DACS-wrap everything, you will likely want to add rules to grant access to various public resources, such as CSS files, robots.txt, favicon.ico, and various public DACS resources, such as its man, dtd-xsd, etc. directories (see the instructions for the Alias directive above). The default ACL acl-stddocs.0 does this for some resources, but you may need to extend the list to grant access to additional public resources.

Initial Configuration


At this point, reviewing dacs.quick(7) is strongly recommended. It provides a detailed example of what needs to be done to make your DACS operational and how to do some basic testing. If you encounter problems installing or running Apache or DACS, please refer to dacs.quick(7).


The interactive dacsinit utility can perform the steps described below quickly. You will find dacsinit in the installation bin directory. It can be run anytime after DACS has been built and installed. It produces a directory structure for the federation, copies the distribution's site configuration file, creates a minimal dacs.conf for the federation and one jurisdiction, makes federation and jurisdiction encryption keys, and generates metadata for the jurisdiction. The resulting configuration can be used immediately by DACS commands and by DACS web services after Apache has been configured for DACS.

Passing the -d flag to dacsinit causes it to append a string to certain paths and filenames so that, for debugging or test purposes, it is unlikely to overwrite any "real" configuration files. Passing it the -n flag causes it to display what it would do without performing any of the actions.

Having installed DACS, the next major step is to do some initial configuration of your federation and jurisdiction(s). At each jurisdiction in your federation you will need to do the following:

  1. Install the default site configuration file. The distribution comes with a default site configuration file found in the distribution's conf/site.conf-std file. The installation procedure copies this file into the DACS federations directory. After making a backup copy of any federations/site.conf file that is already there, copy federations/site.conf-std to federations/site.conf, applying any customizations you require (customizations are usually done in dacs.conf though, so that you can simply copy on top of the previous site.conf). Note that conf/site.conf-std may well change in a new release and you should use the latest version.

  2. As part of the installation procedure, a default set of access control rules is copied into the DACS acls directory (default: /usr/local/dacs/acls). The default site.conf file (site.conf-std) configures DACS to look in that directory for the default rules. These rules control access to DACS web services and are sufficient for proper operation.


    If your installed DACS web services have a filename suffix (e.g., .cgi, you should probably build DACS with an appropriate --with-cgi-suffix flag or customize the rules manually. If it is necessary to change the default rules, consider overriding them at the jurisdiction level instead of editing a default ACL file - this will make it easier for you to upgrade because you will not have to carry these changes forward to future releases of DACS.


    Access to some administrative and experimental DACS web services is completely disabled or restricted by default; change these with care and at your own risk, particularly if your web server is reachable from the Internet.

  3. Configure your dacs.conf file at each jurisdiction. At the very least, you must provide FEDERATION_DOMAIN, FEDERATION_NAME, and JURISDICTION_NAME directives; all other required directives will come from the site.conf file installed in an earlier step if you do not specify them.

  4. Use dacskey(1) to make encryption keys for the federation (if you are creating a new federation) or obtain a copy of the federation's encryption keys for each new jurisdiction (if you are joining an existing federation). Each jurisdiction in a federation must have a copy of the same federation keys.

  5. Use dacskey(1) to make encryption keys for each new jurisdiction (each jurisdiction will have different keys).

  6. Create a group definition that describes your jurisdictions - see dacs.groups(5) - and install an identical copy at each jurisdiction.

  7. Check ownership and permissions on DACS executables and data files.


    All access to DACS configuration files (dacs.conf, site.conf) and keys must be limited to the DACS administrator and the DACS CGI programs called by Apache. The installation process tries to set this reasonably, but you should re-check now and after making changes because it is vital to maintain a secure system (e.g., ls -lR /usr/local/dacs).

Initial Testing

Having configured Apache and DACS, you should try some basic DACS web services to make sure that they are working properly before you go on to make customizations.

For example, invoke dacs_version(8) from your browser to check that it is properly DACS-wrapped (adjust the URL for your environment):

% dacshttp "http://myserver/cgi-bin/dacs/dacs_version"

Review the DACS log files (default: /usr/local/dacs/logs/*) to see what happened. The Apache log files can also be helpful, as messages from mod_auth_dacs can be found there if they have been enabled.

You can also try dacsversion(1) from the command line.

You should verify that dacs_list_jurisdictions(8) works properly.


If your browser successfully retrieves a DACS-wrapped resource it may retain a copy in its cache. A later attempt to retrieve the same resource may appear to succeeed, because the cached copy is returned, even if the DACS configuration or other context has changed so that access to the resource should be denied. To ensure that DACS is handling every request when testing, always clear or disable your browser's cache before beginning. If a request is granted when you expect it to be denied, try the request again, making sure that your browser sends the request to the web server.

The next step is to configure an authentication method - see dacs_authenticate(8) and try to authenticate. Once that appears to be working, you can try dacs_current_credentials(8), dacs_prenv(8), dacs_conf(8), and dacs_signout(8).


Before deploying your DACS-enabled system, after an upgrade, or following configuration changes, always carefully test to ensure that resources are being protected as you require. It is best to configure and test DACS on a development platform that looks as much as possible like the intended production platform. When you are satisfied, a clone of the development platform can become the new production platform, which should also be tested.

Build Options

Running configure generates config.nice (over-writing any previous contents), which can be executed at some later time if you want to re-run configure with the same arguments.


After you are happy with your configuration, consider squirrelling away a copy of config.nice in case you want to reconfigure DACS or for use with later releases of DACS.

It is possible to "bundle" several of the DACS utility programs together into a single binary called dacs. This is similar to what OpenSSL does with its openssl command. Instead of running:

% dacsacl ...

you would run:

% dacs dacsacl ...

Running dacs without arguments displays the list of built-in utilities. Some utilities have multiple names that are equivalent; these appear in a comma-separated list. To build this combined command, add the flag bundle=yes to command lines when building and installing:

% gmake bundle=yes
% gmake bundle=yes install

The commands that are bundled into the dacs command won't be built as separate programs. To build and install both bundled and unbundled commands:

% gmake bundle=both
% gmake bundle=both install

Command: gmake or "gmake build"

This will build libraries, services, and utilities in the source directory. By default, the build process will create shared libraries and binaries if they are supported on your platform.


If you encounter problems while building DACS with shared libraries, use --disabled-shared and --enable-static with configure and try building it again.

Command: "gmake install"

This will install all DACS components. We recommend that everything other than CGI binaries be put under /usr/local/dacs, which is the default. The CGI binaries are by default installed in .../your-apache-dir/cgi-bin/dacs. By default, DACS utilities will be installed in /usr/local/dacs/bin, which you may want to put on your PATH for convenience.

Command: "gmake clean"

Removes binaries, object files, and other junk in the build directory

Command: "gmake distclean"

Does a "gmake clean" and cleans up so that configure can be re-done.

Command: "gmake extraclean"

Does a "gmake distclean" and removes configure. After this, do:

% autoconf -I../include

and then run configure.

Command: "gmake uninstall"

Removes installed binaries, include files, and libraries

Other useful build commands (these should be self-explanatory):

% gmake build-services
% gmake build-progs
% gmake build-static
% gmake build-shared
% gmake build-static-services
% gmake build-shared-services
% gmake build-static-progs
% gmake build-shared-progs
% gmake build-shared-lib
% gmake install-libs
% gmake install-shared-lib
% gmake install-static-lib
% gmake install-progs
% gmake install-services

Configure Options

To verify that this documentation is up-to-date, please run:

% configure --help

This will also tell you which features are enabled (or disabled) by default.

Standard build and install options


The root for the installation hierarchy [/usr/local/dacs], which is referred to as the symbol and variable DACS_HOME.


The root for the architecture-dependent hierarchy [PREFIX].


Where DACS utilities are installed [EPREFIX/bin].


Where DACS libraries are installed [EPREFIX/lib].


Where DACS include files are installed [EPREFIX/include].


Where DACS manual pages are installed [EPREFIX/man].


Generate shared libraries.


Generate static libraries.


Disable prefix path check; the prefix path check does some sanity tests on PREFIX.

Feature selection options


Compile with the authorization caching feature.


Compile with optional add-on features; add-on source code files for the version of DACS being built must be present in the src directory.


Enable all authentication methods; you can use this flag and then individually disable methods (e.g., --enable-all-auth --disable-apache-auth would enable all methods except Apache password authentication.


Enable Apache password authentication directly through DACS.


Enable Berkeley DB support (default is yes); if you don't want it, use the --disable-bdb flag.


Enable CAS authentication.


Enable X.509 client certificate authentication.


Specify default DACS config file.


Specify initial DACS log file.


Compile with debugging.


Compile with development flags and enable development testing.


Use the included fts(3) library.


Enable one-time password grid authentication.


Enable suppression of informational log messages at startup.


Enable InfoCard authentication and support. Deprecated.


Enable Java support.


Enable LDAP authentication and roles.


Enable private DACS roles module. (enabled by default)


Enable authentication via Apache modules.


Enable native Unix ndbm API support (this is often supplied by the Berkeley DB compatibility API).


Enable NTLM authentication.


Enable PAM authentication.


The PAM module should be considered experimental. Test it carefully before production use.


Enable DACS password-protected account authentication.


Enable RADIUS authentication.


Use OpenSSL digests, do not use DACS engine-based code.


Enable extended URL patterns when matching a request against ACLs (this is an add-on feature).


Enable simple DACS account authentication.


Enable SQLite support (default is no). If you don't want it, use the --disable-sqlite flag.


Link to the system libradius library (which must provide a BSD-style RADIUS client API). If RADIUS authentication is enabled and this flag is not given, the portable implementation of the library that is included with DACS is configured, built, and used as a DACS component. Only BSD systems are likely to use this flag.


Enable one-time password token authentication.


Enable Unix groups roles module (enabled by default on Unix platforms).


Compile with the user information reporting feature.

Third-party support options


Root Apache install directory; if DIR is "omit", however, a basic subset of DACS will be installed (also see above) (example: if Apache files have been installed in /usr/local/apache2.4/include, /usr/local/apache2.4/conf, etc., use --with-apache=/usr/local/apache2.4).


Root Apache APR install directory; required only when Apache 2.4 is used (example: --with-apache-apr=/usr/local/apache2.4/apr-httpd).


Apache APR configuration program; required only when Apache 2.4 is used and the correct program is not on the search path; this flag may be required if the build system has more than one instance of Apache installed or if you have installed Apache in a non-standard location (example: --with-apache-apr-config=/usr/local/apache2.4/apr-httpd/bin/apr-1-config).


Preprocessor flags required when compiling files that include Apache APR code; may be required with some "non-standard" cases when Apache 2.4 is used and "apr-1-config --cppflags" is unavailable or does not report the correct flags (example: --with-apache-apr-cpp-defs=-D_LARGEFILE64_SOURCE).


It has been reported that on some GNU/Linux platforms, such as Ubuntu, it is necessary to define these symbols when building DACS code that includes APR header files (such as dacsversion):

#define LINUX 2
#define _REENTRANT
#define _GNU_SOURCE


Apache APR include files directory; required with some "non-standard" cases when Apache 2.4 is used and apr-1-config is unavailable or does not report the correct directory (example: --with-apache-apr-includes=/usr/bin/include/apr-1.0).


Apache APU configuration program; required only when Apache 2.4 is used and the correct program is not on the search path; this flag may be required if the build system has more than one instance of Apache installed or if you have installed Apache in a non-standard location (example: --with-apache-apu-config=/usr/local/apache2.4/apr-util-httpd/bin/apu-1-config).


Apache APU include files directory; required with some "non-standard" cases when Apache 2.4 is used and apu-1-config is unavailable or does not report the correct directory (example: --with-apache-apu-includes=/usr/bin/include/apr-util-1.0).


By default, the build procedure expects the Apache apxs utility to be bin/apxs, relative to Apache's installation directory. On systems where this is incorrect, you must specifically configure the path for apxs. (example: --with-apxs=/usr/sbin/apxs2).


Location of the root of the installed Berkeley DB libraries, include files, etc.; for example --with-bdb=/usr/local/db-5.3.28. This implies --enable-bdb.


Location of Apache CGI files for DACS web services. This will resolve to DIR/cgi-bin/dacs if it exists, or DIR/dacs if that exists, or DIR if its last component is "dacs".


When installing CGI executables, add SUFFIX as the file extension. A typical value for SUFFIX is ".cgi". The default access control rules for DACS web services (via the VFS item type dacs_acls) respect this suffix. On Windows platforms, where ".exe" is the standard extension for programs, SUFFIX is set to that by default. Using a SUFFIX of "no" sets the extension to the null string.


Specify default DACS config file (default: PREFIX/federations/dacs.conf).


Specify initial DACS log file (default: PREFIX/logs/error_log).


Specify a default OpenSSL cipher string specification (the argument to SSL_CTX_set_cipher_list()) to be used with sslclient(1) and therefore by SSL/TLS connections internal to DACS. By default, these connections may use SSLv3 or TLS. By setting CIPHERSTRING appropriately, connections can be restricted to TLS, for instance. This is separate from any Apache SSL/TLS configuration.


Specify the default behaviour for how DACS should verify the identity of a peer when an SSL/TLS connection is established. Although DACS generally only initiates connections (i.e., acts as a client), a few optional components act as a server. By default, the original "server match" algorithm is used (METHOD is dacs). To use OpenSSL peer verification instead, specify METHOD as openssl. If it is necessary to turn off peer verification, you should specify METHOD as any of none, disable, disabled, or off. The default behaviour for a particular application or context can be overridden by a command line flag or configuration variable. Refer to sslclient(1) for additional information.


Root directory of installed Expat libraries and include files. If Expat files have been installed in /usr/local/expat/include, /usr/local/expat/lib, etc., use --with-expat=/usr/local/expat.


Location of DACS federations root directory (default: PREFIX/federations).


Enable ndbm support using gdbm's compatibility API (gdbm(3)), specifying the include flags to use. (Example: --with-gdbm-includes=-I/local/src/gdbm-1.23/include). (CentOS Example: --with-gdbm-includes=-I/usr/include/gdbm).


Enable ndbm support using gdbm's compatibility API (gdbm(3)), specifying the link flags to use, the pathname for the library, and any other necessary flags. (FreeBSD Example: --with-gdbm-lib="-Wl,-rpath,/local/src/gdbm-1.23/lib -L/local/src/gdbm-1.23/lib -lgdbm"). (CentOS Example: --with-gdbm-lib="-L/usr/lib64 -lgdbm").


Location of Apache DACS files if not the htdocs subdirectory of the Apache install directory.


Path to parent of iconv installation. This flag may be required if you are enabling Samba support.


If Java support is enabled, this identifies the directory containing the java, javac, javah, and jar commands. If this flag is absent, configure will look for those programs using the current PATH variable. (Example: --with-jdk-bin=/usr/local/java/bin).


If Java support is enabled, this is a list of one or more GCC include flags for JDK include directories (Example: --with-jdk-includes="-I/usr/local/jdk/include -I/usr/local/jdk/include/freebsd").


Location of OpenLDAP source files. This is the root directory for the OpenLDAP source distribution (Example: /local/src/openldap-2.6.8). This implies --enable-ldap-auth.


Location of the libdsm library (which will be used instead of Samba). This is the root directory of the library's source distribution. This option implies --enable-ntlm-auth, which may also appear explicitly, but is incompatible with --with-samba.


Location of a mailer program to use instead of sendmail. This is only needed if email support is required. If --with-mail-args is also specified, it will be used as the command line arguments. See dacsemail(1) for a description of how the mailer is expected to behave.


Command line arguments to use with the selected mailer program. This is only required if email support is required. See dacsemail(1) for a description of how the mailer is expected to behave.


Use GNU Readline when available. If LIB is given, it is the link flag to use or the pathname for the library (other flags may also be specified). (Example: --with-readline="-Wl,-rpath,/local/src/readline-8.2/lib -L/local/src/readline-8.2/lib -I/local/src/readline-8.2/include").


Location of Samba source files. This is the root directory for the Samba source distribution (Example: /local/src/samba-3.6.25). This implies --enable-ntlm-auth.


Location of sendmail(8). This is only needed if email support is required and the location of the sendmail command found at configuration time must be overridden. If --with-mailer-args is also specified, it will be used instead of the default sendmail command line arguments. See dacsemail(1) for additional details.


Location of the root of the installed SQLite libraries, include files, etc.; for example --with-sqlite=/usr/local/sqlite-3.46.0. This implies --enable-sqlite.


Location of the root of the installed OpenSSL libraries and include files. If OpenSSL files have been installed in /usr/local/openssl/include, /usr/local/openssl/lib, etc., use --with-expat=/usr/local/openssl.


If the build procedure cannot find xmlsec1-config, or if it finds the wrong one, you can specify its location as PATH. This may only be required if InfoCard authentication has been enabled. Deprecated.

To specify additional flags for compiling or linking DACS, set CFLAGS or LDFLAGS, respectively.

To specify additional flags for compiling or linking the mod_auth_dacs module, set APACHE_CFLAGS or APACHE_LDFLAGS, respectively. For example, this command will cause mod_auth_dacs to be built with the -m64 flag and DACS to be built with both the -m64 flag and the -O3 flag:

% ./configure "APACHE_CFLAGS=-m64" "CFLAGS=-O3 -m64" ...


dacs(1), dacs.readme(7), dacs.quick(7)


Distributed Systems Software (www.dss.ca)


Copyright 2003-2024 Distributed Systems Software. See the LICENSE file that accompanies the distribution for licensing information.

DACS Version 1.4.51 20-Jun-2024 DACS.INSTALL(7)

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$Id: dacs.install.7.xml 3327 2024-06-20 22:15:52Z brachman $