Ubuntu Manpage: negotiate_kerberos_auth - Squid kerberos based authentication helper

Provided by: squid_3.5.12-1ubuntu7.16_amd64

NAME

       negotiate_kerberos_auth - Squid kerberos based authentication helper

       Version 3.0.4sq

SYNOPSIS

       negotiate_kerberos_auth   [-h]   [-d]   [-i]   [-r]  [-s  Service-Principal-Name]  [-k  Keytab-Name]  [-c
       Replay-Cache-Directory] [-t Replay-Cache-Type]

DESCRIPTION

       negotiate_kerberos_auth is an installed binary and allows Squid to authenticate users via  the  Negotiate
       protocol and Kerberos.

OPTIONS

       -h          Display the binary help and command line syntax info using stderr.

       -d          Write debug messages to stderr.

       -i          Write informational messages to stderr.

       -r          Remove realm from username before returning the username to squid.

       -s Service-Principal-name
                   Provide Service Principal Name.

       -k Keytab-Name
                   Provide Kerberos Keytab Name (Default: /etc/krb5.keytab)

       -c Replay-Cache-Directory
                   Provide Replay Cache Directory (Default: /var/tmp)

       -t Replay-Cache-Type
                   Provide Replay Cache Type (Default: dfl)

CONFIGURATION

This helper is intended to be used as an authentication helper in squid.conf.

auth_param negotiate program /path/to/negotiate_kerberos_auth
auth_param negotiate children 10
auth_param negotiate keep_alive on

NOTE: The following squid startup file modification may be required:

Add the following lines to the squid startup script to point squid to a keytab file which contains the
HTTP/fqdn service principal for the default Kerberos domain. The keytab name can also be provided by the
-k <keytab name> option. The fqdn must be the proxy name set in IE
or firefox. You can not use an IP address.

KRB5_KTNAME=/etc/squid/HTTP.keytab export KRB5_KTNAME

If you use a different Kerberos domain than the machine itself is in you can point squid to the seperate
Kerberos config file by setting the following environmnet variable in the startup script.

KRB5_CONFIG=/etc/krb5-squid.conf export KRB5_CONFIG

Kerberos can keep a replay cache to detect the reuse of Kerberos tickets (usually only possible in a 5
minute window) . If squid is under high load with Negotiate(Kerberos) proxy authentication requests the
replay cache checks can create high CPU load. If the environment does not require high security the
replay cache check can be disabled for MIT based Kerberos implementations by adding the below to the
startup script or use the -t none option.

KRB5RCACHETYPE=none export KRB5RCACHETYPE

If negotiate_kerberos_auth doesn't determine for some reason the right service principal you can provide
it with -s HTTP/fqdn.

If you serve multiple Kerberos realms add a HTTP/fqdn@REALM service principal per realm to the
HTTP.keytab file and use the -s GSS_C_NO_NAME option with negotiate_kerberos_auth.

AUTHOR

       This program was written by Markus Moeller <markus_moeller@compuserve.com>

       This manual was written by Markus Moeller <markus_moeller@compuserve.com>

COPYRIGHT

        * Copyright (C) 1996-2014 The Squid Software Foundation and contributors
        *
        * Squid software is distributed under GPLv2+ license and includes
        * contributions from numerous individuals and organizations.
        * Please see the COPYING and CONTRIBUTORS files for details.

       This program and documentation is copyright to the authors named above.

       Distributed under the GNU General Public License (GNU GPL) version 2 or later (GPLv2+).

QUESTIONS

       Questions  on  the  usage  of  this  program  can   be   sent   to   the   Squid   Users   mailing   list
       <squid-users@squid-cache.org>

REPORTING BUGS

       Bug  reports  need  to  be  made  in  English.  See http://wiki.squid-cache.org/SquidFaq/BugReporting for
       details of what you need to include with your bug report.

       Report bugs or bug fixes using http://bugs.squid-cache.org/

       Report serious security bugs to Squid Bugs <squid-bugs@squid-cache.org>

       Report ideas for new improvements to the Squid Developers mailing list <squid-dev@squid-cache.org>