Fixing Postfix in Panther
As the user of a 12" PowerBook, I found early on that sending mail outside my own ISP domain was going to be a pain - BT Openworld don't appear to allow access to their SMTP servers outside their own IP block, even if you use authentication. This is all very noble in the name of spam-fighting, but pretty hopeless in letting me send e-mail away from home.
Step forward however, David Reitter's article on installing Postfix on OS X. This has been working an absolute treat until today when I upgraded to OS X to 10.3 Panther whereupon it promptly stopped dead.
To cut a long story short - after mucking around recompiling and all that flannel, the thing that cracked it was taken from this article on comp.sys.mac.system. Specifically, editing /etc/postfix/master.cf to uncomment out the line beginning smtp, followed by ensuring the mailserver entry in /etc/hostconfig is set to -YES- (Panther chose to set it back to -NO- it seems).
Your mileage may vary of course, but that post is a good a place as any to start.