Best way to block outgoing port 25

[osnanderson]

Hello

Can you tell me the best way to block the outgoing port 25 completely on the server?

I tried removing the outgoing IPV4 port from the CSF firewall configuration, but still emails are being sent from cPanel. I wanted to completely block port 25 so no emails are sent from the server.

Would you know how to help me?

Thank you

 

[cPRex]

Hey there! If you don't want any email sent, you could just disable Exim so it isn't running. Inside CSF there is also this option:

# This is a comma separated list of the ports to block. You should list all
# ports that exim is configured to listen on
SMTP_PORTS = "25,465,587"

so you'll want to remove the ports you don't want active in the firewall from that list.

 

[osnanderson]

I'll explain my situation better:

I want to completely block outgoing emails through port 25, but allow sending emails to some accounts via smarthost on another port. So I believe disabling exim would not work.

Do you know how to do this total blocking of outgoing port 25?

 

[cPRex]

Did you try that CSF settings I mentioned?

 

[osnanderson]

Did you try that CSF settings I mentioned?

I didn't understand well about this SMTP_PORTS option. Would it be enough for me to remove port 25 from SMTP_PORTS and that would prevent emails from going out through that port 25?

 

[cPRex]

Yes, that should be all that is needed.

 

[quietFinn]

I believe you also need SMTP_BLOCK = ON in CSF.