Trying to open for E-mail out only, but I'm stumped



  • I want one of my segments to be able to send mail, but nothing else. So I have opened for port 2525 (non-standard SMTP port), but no way. If I remove the port (so I open for everything), it works. Are there other ports that I need to open to send mail? I have the net as source, TCP/UDP as the protocol, any destination and source port, and then any destination and port 2525, and any gateway. Shouldn't that work?



  • @mastiff said in Trying to open for E-mail out only, but I'm stumped:

    Are there other ports that I need to open to send mail?

    Maybe. It depends on what you're doing.

    Shouldn't that work?

    If it's properly configured. if you don't know why it's failing, look at your firewall block log. If you only allow tcp/25 from LAN, then what is being blocked while trying to send mail? The logs will show you and then you can account for that blocked traffic to let it flow. Repeat until it all works.



  • Thanks! Found it. Idiot mistake... I just needed to open for DNS, so port 53 to the firewall itself. I had forgotten that the mail server is a domaine name, not an IP address. 😱