[CLUE-Tech] Point MUA to local SMTP listener?

[Matthew Porter]

I'm configuring Sylpheed as my mail user agent on a Debian Woody system, and I'm stumped as to one thing: How do I send outgoing mail to my local machine's SMTP program?

I have Exim running. It works fine for incoming internet mail (and deals with mail generated by local programs such as Anacron), and a test with telnet localhost 25 or telnet 127.0.0.1 25 tells me that exim is listening for smtp connections.

But how do I send messages from my MUA to that SMTP port?  Do I need to add some entry for my local smtp program to /etc/hosts?  Or can I identify my local smtp port by some numerical IP address?  I feel like I'm missing something simple, but for now I'm stumped.

(The reason I'm trying to send all outgoing mail through exim is so that mail to other users on this local machine get delivered to their local mailboxes, and mail to outside internet addresses get sent out via my dialup.  Is this a reasonable approach, anyway?)

Thanks,

 --Matt.