It looks like my old post disappeared. Search profile posts says I am not found. So I am starting a new post.
I have VPS with fresh install of debian 11. I have open port: 22 Secure Shell (SSH). I have closed port: 25 Simple Mail Transfer Protocol (SMTP). I am trying to open port 25. I am not try to change the port numbers, I am simply trying to open one more port. As one port is open and the rest are closed, I guess that a firewall is installed and running. Or what else can cause this? And how to fix this?
I have VPS with fresh install of debian 11. I have open port: 22 Secure Shell (SSH). I have closed port: 25 Simple Mail Transfer Protocol (SMTP). I am trying to open port 25. I am not try to change the port numbers, I am simply trying to open one more port. As one port is open and the rest are closed, I guess that a firewall is installed and running. Or what else can cause this? And how to fix this?