                                 SquidGuard

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  What to do with Active Directory Referals?

   If your Active Directory Servers answers an LDAP request with referals
   the autentication is likely to fail.
   Below you find user responses how they got around this problem:
    1. By Alan Walker, Sep 2008:

   Just an FYI for the record in case somebody else sees the same issue in
   the future:
   Our squidGuard has been performing well for months now, with Squid
   performing NTLM authentication and squidGuard performing LDAP lookups
   to check whether a particular user is in a particular group, and so
   block certain sites to certain users and allow them to others. However,
   once in a while the squidGuard logs would report:
   2008-09-03 09:18:53 [2962] (squidGuard): ldap_search_ext_s failed:
   Operations error (params: dc=ticgroup,dc=local, 2,
   (&(memberof=CN=InternetGeneral,OU=Groups,OU=Altona,DC=ticgroup,DC=local
   ) (sAMAccountName=awalker)), sAMAccountName)
   Which would result in a blocked page, and the user would have to close
   the browser and wait a few minutes before resuming happily. Minor
   inconvenience, but not too bad.
   However, yesterday, for no apparent reason, this error started
   happening on EVERY account, so nobody could access the web.
   To cut a long story short, I think that the Windows Active Directory
   server which was being searched by SquidGuard started generating
   referrals to other systems (for more complete information) for any
   searches in the active directory at the root level (although for lower
   levels it was happy to supply the information with no referrals, I
   really don't know why, I'm just treading water at this depth), and the
   system did not have the credentials/trusts/whatever (Kerberos?) setup
   required to follow the referral to wherever it needed to go (don't ask
   me where, I still don't fully understand this).
   The workaround/solution was to stop using a regular AD server to
   perform the searches and go straight to the domain Controller (is there
   really such a thing in AD?) and query the Global Catalog on port 3268
   instead of the regular LDAP query port of 389. Apparently the Global
   catalog does not do referrals, it just supplies all of the information
   itself (Thank you Global Catalog). Maybe just setting up Kerberos
   properly would be a better solution, but that's in the "too hard"
   basket at the moment.
   So my search line in the squidguard.conf changed from:

   ldapusersearch
   ldap://ticmelb1/dc=ticgroup,dc=local?sAMAccountName?sub?(&(memberof=CN=
   InternetGeneral%2cOU=Groups%2cOU=Altona%2cDC=ticgroup%2cDC=local)(sAMAc
   countName=%s))

   to:

   ldapusersearch
   ldap://tic_group_dc.ticgroup.local:3268/dc=ticgroup,dc=local?sAMAccount
   Name?sub?(&(memberof=CN=InternetGeneral%2cOU=Groups%2cOU=Altona%2cDC=ti
   cgroup%2cDC=local)(sAMAccountName=%s))

   and now the system is happy again.
   Hope this helps somebody. (Also hope it keeps on working for me.)

   [8]Documentation
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   [9]Installation
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   Configuration
    [10]Getting started
    Destination ACLs
    Source ACLs
    [11]Redirect Rule
    [12]Time Constraints
    [13]Authentication
    [14]Regular Expressions
    [15]Examples
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   [16]Runtime Options
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   [17]About blocking
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   [18]Troubleshooting
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   [19]Known Issues
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   [20]Other Sources
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References

   1. http://www.squidguard.org/index.html
   2. http://www.squidguard.org/download.html
   3. http://www.squidguard.org/Doc/
   4. http://www.squidguard.org/Devel/
   5. http://www.squidguard.org/blacklists.html
   6. http://www.squidguard.org/Contrib/
   7. http://www.squidguard.org/impressum.html
   8. http://www.squidguard.org/Doc/index.html
   9. http://www.squidguard.org/Doc/install.html
  10. http://www.squidguard.org/Doc/configure.html
  11. http://www.squidguard.org/Doc/redirect.html
  12. http://www.squidguard.org/Doc/extended.html#times
  13. http://www.squidguard.org/Doc/authentication.html
  14. http://www.squidguard.org/Doc/expressionlist.html
  15. http://www.squidguard.org/Doc/examples.html
  16. http://www.squidguard.org/Doc/runtimeops.html
  17. http://www.squidguard.org/Doc/aboutblocking.html
  18. http://www.squidguard.org/Doc/troubleshoot.html
  19. http://www.squidguard.org/Doc/known_issues.html
  20. http://www.squidguard.org/Doc/other_sources.html
  21. http://www.shalla.de/
