Cannot connect to remote port 25 from XP Pro workstations

[humbletech99]

I have a strange issue in that I cannot connect to remote port 25 from windows xp workstations. Some workstations are ok, and this works, some are not.

All these workstations are in a windows 2003 domain and all are xp sp2. I've seen this before but not found a solution. All the workstations here have their firewalls enabled with the same configuration via GPO.

So all I can think of is that microsoft's crippled tcp/ip stack is responsible for this in some lame attempt to reduce spam or something, but we need this as it stops some legitimate processes from running (for example command line utils and python programs that need to send notification emails etc)

Does anybody know anything about this or how I can get around it?