Hi, I have ISPConfig 3.1 setup (Perfect setup on Debian Stretch), and run into problem - on one of the remote location ISP blocked port 25 and refused to change this because of corporate policy. How we can have both ports 25 and 465 active ? Thanks in advance.
Incoming (smtp) Ports 25, 465 and 587 are active by default on your server when you followed the perfect server guide to install your system. You can check which ports are open by using the commands: netstat -ntap
But: Mails won't come in on port 465! So a server that cannot use port 25 is NOT able to communicate with external mail servers. If it's only your client's location where the port is blocked, you should re-check the perfect server tutorial as till mentioned.
ISPConfig is on another site, where ISP don't close any port. Only e-mail clients (on remote area) need connection from problematic ISP. I opened 465 port on ISPConfig firewall and everything is OK now. How I could miss that from the beginning? Thanks everyone for help !
