Static one-to-one NAT possible?

[TabHelp]

Hi,

We're using WinGate 8 and have several interfaces in use on that host.

On the Internet interface we have more than one public IP address (/29 subnet) available.
One of those addresses is used for incomming e-mail (SMTP) and is serviced by WinGate through
the a 'TCP Mapping Service'.

I wonder if it's possible for outgoing SMTP traffic to also be translated to that specific IP address?
A one-to-one NAT so to speak. Sometimes refered to as Static NAT.

The reason I want this is that some spam filters compare SMTP sender addresses to the sender domain
MX records. When no match is found, the e-mail gets a higher spam score. This kind of spam check
is common nowadays.

Thanks for your reply in advance.

Best regards,

Rob

[adrien]

HI Rob

Is your internal mail server sending directly, or relaying through WinGate's SMTP server/delivery service?

If directly, you can

* use a TCP mapping proxy on some port (any)
* intercept port 25
* disable default mapping, and don't add any mappings.

This will make the TCP mapping proxy connect to the original intercepted destination.

then specify in the gateways tab which gateway to use, and for your case, which local IP to bind to first.

If you're using SMTP store/forward in WinGate, you can just configure the SMTP delivery service in the same way (in terms of the gateways tab).

Regards

Adrien