bsamuels@beenthere-donethat.org.uk writes:
I have a small home network of just two machines. Machine1 runs Debian Testing with Exim and Procmail. Machine2 is running Mandrake 9 with Postfix.
I have just spent about two half-days trying to set things up so that I can send mail from one machine to another. After having spent hours searching for information on both my own machine and on the Internet I have to admit defeat.
When I try to send mail from a user on either machine to a user on the other I get the following message:
'Host lookup did not complete'
Sounds like a DNS problem to me; make sure that's all working properly before trying to do mail.
I don't know about Exim but some MTAs (and some other applications) do not look at /etc/hosts for some/all DNS lookups (which is hardly surprising given that it's impossible to encode an MX record in a hosts file). For these applications to work you must have your hostnames in DNS as well (or instead).