preventing postfix from listening on port 25

tklima · 01-07-2008, 02:47 PM

Hi,

how can I prevent postfix from listening on port 25? I want postfix to be used for sending mails from the local system only, not as a mail server.

I am running Debian (2.6.18-5)

Thanks for you help.

acid_kewpie · 01-07-2008, 02:54 PM

it will always need to listen on 25 locally, but you can stop it listening externally by using the inet_interfaces option, e.g. "inet_interfaces=localhost" in your main.cf

trickykid · 01-07-2008, 04:12 PM

Or just use iptables to block all incoming or outside port 25 requests outside of your local network. Allow outgoing though.

zoranp · 01-07-2008, 05:04 PM

Or just do not run postfix in daemon mode.

Eduardo Nunes · 08-30-2010, 11:55 AM

Quote:

Originally Posted by tklima

Hi,

how can I prevent postfix from listening on port 25? I want postfix to be used for sending mails from the local system only, not as a mail server.

I am running Debian (2.6.18-5)

Thanks for you help.

If you want to use the "sendmail" command to send emails, you may comment out the smtp inet n - n - 1000 smtpd line at master.cf

You can also block out the port 25 for incoming connections with iptables.

# iptables -I INPUT -p tcp --dport 25 -j DROP

Berhanie · 08-30-2010, 12:06 PM

You might consider putting this in main.cf:

Code:

inet_interfaces = loopback-only

This causes the postfix smtpd to listen only on the loopback interface, making connections from external hosts impossible. You should read the STANDARD_CONFIGURATION_README and its prerequisites.
[edit]i see acid_kewpie already gave the same advice. just add my vote to his reponse.[/edit]