Software :: Using NAT And Want To Do Intranet Email Using IP Addresses Instead Of Names

I've got 2 computers plugged into an "ethernet broadband router" sitting behind a DSL modem. I'd like to be able to send mail from one of the 2 computers to the other, preferably without going through the DSL modem, and preferably without assigning host names (if that's possible).

I've installed/configured sendmail (and sendmail-cf and m4) and am attempting babystep tests of the configuration by sending mail to a user on the originating computer.

So I can send email to root@localhost and it is received on the local host.

But if I try to send it to root@127.0.0.1, it bounces back like so:

This seems to be pretty fundamental (the localhost has an address of 127.0.0.1). Shouldn't I be able to use the IP address in place of the associated name?

Here's my hosts file /etc/hosts:

Code:

And here's my resolv.conf file, although I wouldn't expect that to come into play since I'm using IP addresses instead of names /etc/resolv.conf:

Code:

Here's my /etc/mail/access file:

Code:

I did verify that sendmail was configured to listen in on more than just the loopback address in /etc/mail/sendmail.mc, but that doesn't seem to be relevant until I can get email through to 127.0.0.1.

Which files do I need to create/touch to get this to work?

And can it be done without talking to the DSL modem?