[exim] Very weird e-mail problems

Hello everyone,

I'm completely confused, so I will try to explain my situation as best
as possible.

We have two mail servers. One is running Exim, and the other is running
Postfix. I'm posting this e-mail to both mailing lists to see if I can
track down the problem, although I do not think it is Exim (which I will
explain).

On the mail server that is running Exim, we have a catch-all that sends
all mail from the domain foo.com which is located on the Exim server to
person@??? which is located on the Postfix server. For some reason,
it never arrives to the Postfix server. I took a look at the Exim logs,
and they show that the e-mail is being sent successfully, but when I
tail the logs on the Postfix server, I never see an e-mail arrive.

I can set up a forward/catch-all on the Exim server to forward all mail
to my gmail account, and I get the e-mails instantly. This is why I
don't think it is the Exim server, but I could be wrong.

Now, here's the very weird part. If I e-mail any e-mail address on the
Postfix server directly, the e-mail is received. However, when I
forward mail from an email address on the Exim server to an email
address on the Postfix server, the Exim logs say it's been sent but the
Postfix logs never say anything, whether it has failed or been successful.

We haven't had any other complaints from anyone else, so I don't know
how to track this problem down. Like I said, I checked all the logs,
and nothing seemed out of the ordinary.

Hopefully I'm not being too vague, and if I need to provide any more
information to help you folks troubleshoot, please let me know and I
will be more than happy to supply anything you might need.

Thanks to all in advance!

Patrick