[courier-users] Why my mail don't reach some hosts?

[Vitaly Voropinov]

Hi peoples   I've got some problem on FreeBSD 4.2. Mail don't reach some hosts and their mail don't reach mine one. What may it be? Error in log file: Connection unexpectedly closed by remote host. Why? I really don't know. I think that be a firewall denying but it was absolutely inactive and problem stay all time :(   I'm not expert with Courier and Unix-system, I'm beginner :) Please help me! (may be better to install another mail server?)   Regards Vitaly Voropinov