Allow sendmail on just one adapter. 1

[motoslide]

I hope I can describe this properly.
We have a new sendmail server with 2 network adapters.
(these addresses are just examples, they are not ours)
Adapter-A: Public IP (i.e. 132.147.160.10)
Adapter-B: Private IP (i.e. 192.168.1.10)
I want sendmail to only allow inbound mail on Adapter-B. It will still handle internal and internet mail, but incoming SMTP traffic is protected by an outside spam filtering service, then forwarded to that IP by our router.
Outbound mail can use either Adapter, but it seems it would be easiest to block sendmail on Adapter-A altogether.
System is running SCO OpenServer6.


"Proof that there is intelligent life in Oregon. Well, Life anyway.

 

[jkupski]

SCO? Bleh.

It's been about five years since I've used OpenServer, but I think that more recent versions come with a netfilter (iptables) based firewall. Is that correct?

If so, just block port 25 for everything except 192.168.1.0/24 and you're good to go.

 

[motoslide]

Thanks for the advice. I got side-lined on other projects.
This worked. I just blocked all port 25 traffic from all adapters, then added another rule to allow it as you stated.

"Proof that there is intelligent life in Oregon. Well, Life anyway.