This post explains how to setup a Squid HTTP proxy to transparently authenticate users against a Novell eDirectory. In the Novell eco-system Border Manager is the venerable choice for an internal firewall and proxy but it is showing its age. This guide is based on this Novell Cool Solution. Unlike Border Manager, which requires the CLNTRUST client-side tool, the setup described works without the need for any desktop client software.
How it works
Within a Novell managed network the eDirectory stores authenticated user's I.P. addresses. Squid performs an LDAP search against eDirectory using the incoming I.P. address of the client. If successful the authenticated username is returned and a proxy session established. If the search comes up empty Squid prompts the client to manually enter their credentials for authentication against the eDirectory. If this too fails the proxy request is denied.
eDirectory 8.8 incompatability
This solution currently only works with eDirectory < 8.8 because Novell has slightly changed the format they store network addresses in newer versions. At the time of writing I have not been able to test against eDirectory 8.8 so I cannot determine the required code changes or test results. Hopefully in the near future this situation will change.
Squid's external_acl_type option
Transparent authentication is made possible thanks to Squid's external_acl_type configuration option. This allows external identities and groups to be identified via any external script. Once Squid is installed setting up transparent eDirectory authentication is a two step process:
- Create and tweak the squid_edir_iplookup.pl file.
- Edit the squid.conf configuration file