firewall outgoing mail

is it possible to add a fire wall that will stop a server from sending
any outgoing mail,
I'm having spam problems with my server, ( it is sending spam) i want
to stop it from sending any mail at all.

I'm guessing that mail is sent to a fixed port number on other
servers, so can i make a firewall to stop programs from sending data
to a port on any remote server.

is this right?

iptables -I FORWARD 1 -p tcp --dport 25 -j DROP

i only have a remote server so I don't want to firewall myself out of
it, can someone help me.

On Sep 29, 4:42 pm, Maxwell Lol <nos...@com.invalid> wrote:
> elie <mazz...@gmail.com> writes:
> > is it possible to add a fire wall that will stop a server from sending
> > any outgoing mail,
>
> Sure. Block outgoing conections to the SMTP port - 25.

And port 587. Port 25, SMTP, = "transport", 587 is email injection.
Many
ISPs block port 25 now in a misguided attempt to stop spam.

Thad Floryan wrote:
> On Sep 29, 4:42 pm, Maxwell Lol <nos...@com.invalid> wrote:
>> elie <mazz...@gmail.com> writes:
>>> is it possible to add a fire wall that will stop a server from sending
>>> any outgoing mail,
>> Sure. Block outgoing conections to the SMTP port - 25.
>
> And port 587. Port 25, SMTP, = "transport", 587 is email injection.
> Many
> ISPs block port 25 now in a misguided attempt to stop spam.

And tcp/465 for smtps. How long before ISPs block them all, I wonder?

guys can someone verify that this is the right syntax

iptables -I FORWARD 1 -p tcp --dport 25 -j DROP

I'm afraid to add it and have my remote server disappear from the
internet.


On Sep 29, 8:03*pm, elie <mazz...@gmail.com> wrote:
> is this right?
>
> iptables -I FORWARD 1 -p tcp --dport 25 -j DROP
>
> i only have a remote server so I don't want to firewall myself out of
> it, can someone help me.

added, thanks for the help.