[Exim] Setting the IP address

Hi. I have a machine with 4 IP addresses (aliases), exim uses
the one bound to eth0:2 rather than just eth0 it seems.

Received: from www.job2000.dk ([129.142.225.157]) by mail.it-c.dk
    (8.9.3/8.9.3) with ESMTP id MAA03979 for <morten@???>; Thu,
    17 Jan 2002 12:11:36 +0100

[root@job2000 etc]# host www.job2000.dk
www.job2000.dk. has address 129.142.225.154

Where does exim get the IP address from? I would expect /etc/hosts
or a DNS lookup. The docs hint uname, but I cannot see any relation
between my uname -a and the IP exim uses.

Is there a way I can explicitly set the IP address?

Thanks

Morten