- Plesk for Linux
Is it possible to use another port for SMTP connection if 25 port is blocked by ISP?
Usually, ISP blocks only outgoing 25 port. There are two options:
- Contact ISP and ask to unblock 25 port for outgoing traffic.
- Setup relayhost(smarthost) in postfix following steps from any 3rd-party resource like this.
If ISP also blocks incoming 25 port, it will be impossible to use mail service on this server. Anyway, contact ISP for assistance.