Binding SMTP service into IP tables, and redirecting SMTP to port 366
 

Hello

I sure hope someone here can help us with this. Our server runs CentOS version 5.1.

We just had our sys admin open port 366 on our firewall since we have some customers in the US that use Comcast as their main ISP and apparently the've recently blocked port 25 from all their servers, which of course prevents their users from sending mail normally thru that port.

However we've been told that there is actually a way around that issue if we use port 366 instead.

So my question is just this:

How do you tell IP tables, in other words what's the line (or lines) we need to add in the IP tables config file and most importantly, what is the name of that file and in which folder is it supposed to be?

Thanks for all your help, it is appreciated.

Bamquest6

I'm afraid for a useful answer, you will need to supply more information.

Firstly, when you say that you have "had our sys admin open port 366 on our firewall" do you mean that this firewall (the one on which you have already opened 366) is a different firewall from the iptables firewall on which you now want to make a change?

Assuming that was the correct interpretation, you need to find out how your existing iptables firewall rules are being created. Probably, the three most popular options are:

• from a graphical front end, prefereably, for security purposes from a different machine
• from a bash script (or other scripting language)
• 'manually' using 'iptables -L' to dump and append/insert

...while you could always create the effect that you want on a one off bassis 'by hand', if, the next time that you reboot, something else kicks in, you'll want to have control of the thing that writes the rules at a reboot.