I've looked through some of the mailing list archives and can't find anything specific on kerberos authentication to a MIT KDC for windows clients. Everything I've found mentions AD. What I'd like, if possible, is to have single sign on capabilities to between OS X server's Open Directory, squid 2.7stable9 on CentOS 5.5, and Windows XP clients. With pGina and kerberos for windows installed on the XP clients, I successfully get a ticket from the OD server. What I'm having problems with is getting firefox or IE to use the ticket for negotiation with the squid server. I'm guessing that I've missed setting up a principal correctly, copied keytab, or possibly a DNS issue but I'm not familiar enough with kerberos to know what's wrong. Packet captures for kerberos return KRB-ERROR like this after the TGS_REQ when opening a browser session with FF: Kerberos KRB-ERROR Pvno: 5 MSG Type: KRB-ERROR (30) ctime: 2010-12-03 21:05:34 (UTC) stime: 2010-12-03 21:05:26 (UTC) susec: 714271 error_code: KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN (7) Client Realm: XSERVE.PARAGOULD.PSD Client Name (Principal): HTTP/proxyserver.paragould.psd Name-type: Principal (1) Name: HTTP Name: proxyserver.paragould.psd Realm: XSERVE.PARAGOULD.PSD Server Name (Unknown): krbtgt/xserve.paragould.psd Name-type: Unknown (0) Name: krbtgt Name: xserve.paragould.psd e-text: UNKNOWN_SERVER If anyone has any ideas or what to look for, I'd appreciate any help. If this isn't enough information from the capture to make an educated guess as to where I need to look further, I have the entire sequence I could post as well. Thanks, Rob ---------------- Rob Asher Network Systems Technician Paragould School District 870-236-7744 x169 ---------- This message has been scanned for viruses and dangerous content by the Paragould School District MailScanner, and is believed to be clean.