One of my coworkers has been getting this error when he tries to log into our SQL Server 2005 instances from home. What we have found strange is that he can connect to any of the instances using his laptop when he's plugged in at the office, but he gets the "Cannot generate SSPI context" error when he tries to connect from home. We have Juniper for the VPN and he can access other network resources when he's connected. When I connect from my house and try, I have no problems connecting to the SQL Server instances.
I've tried checking profiler and logs when he's made connection attempts, but I don't see anything. We've been digging around at this for several days now and tried checking quite a few things. His login looks alright, we've tried pinging the server, flushing the DNS on his machine. Just can't figure it out.