[Exim] Migration

I am migrating off a Linux (cobalt using sendmail - double yuck) to a
penguin Linus box (RH7)running Exim. The cobalt hosts mail and DNS for a
number of domains, and I'm beginning to get a decent grasp off all that I
will need to do. I am hoping there are a few of you out there who can make
some suggestions as to 'gotchas' that I should be aware of during the
move. I am moving most of the accounts straight over, leaving the UIDs as
they are. A few of the hiccups I foresee are in regards to the complex
config that the Cobalt has in the majordomo list server, but I will sort
through that slowly.

Any advice or warnings that you people can think of and fire my way would
be greatly appreciated...

Thanks in advance.

derrick


PS - Sorry for a sendmail question, but how do you allow non-existent
accounts to be included in the /etc/aliases file? Trying to avoid
creating some accounts on the clunky Cobalt interface... TIA