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 separate Kerberos config file by setting the following environment 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.
This manual was written by Markus Moeller <email@example.com>
* 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.
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