Postfix Mailserver; Blocked Port 25
I've used this lenny mailserver setup to get my mailserver working, but it doesn't. Hmm..., my bad.
It works fine locally, going from firstname.lastname@example.org to email@example.com, but it fails to send or receive with all external domains.
Now, my ISP blocks port 25, to quote:
Connections made to Port 25 (the standard SMTP port for outbound email) that are not directed toward this ISP's Email server are blocked.
To manoeuvre around this, my router redirects incoming port 26 connections to port 25 on the mailserver.
As mentioned, sending email via this server works alright up until it tries to connect to the external domain. If I send an email everything works, but postqueue shows the email in limbo because it could not connect to the external-domain mailserver.
I'm using postfix, dovecot, amavis, spamassassin, clam-av, with a mysql database. I am fairly certain my problems are due to my ISP's blocklist -but what do you think?