Re: [Exim] can't send large email messages

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Author: michael
Date:  
To: exim-users, steve
CC: don, mknapp
Subject: Re: [Exim] can't send large email messages
> I can't send large email messages from exim 3.12 (debian) to an Exchange
> server when passing packets through a CISCO PIX Firewall.


This has annoyed us to no end, but there is an easy solution. Our PIX did
something special with SMTP connections and disabling that feature got rid
of the problem. I can ask for the exact command, firmware release etc,
but I don't know it or any further details. Our firewalls only allow
traffic from the large mail cluster, which acts as primary MX for all
domains hosted behind firewalls, so special SMTP processing is not needed.
Things might look different for you.

IMHO the PIX is broken in that respect, because some mails got through
after various retries, some always got through and some never made it.
It does not really depend on the size. Things are worse: The Exchange
system got the mails, the connection timed out after the end of data,
and Exchange delivered them just fine, whereas Exim made a retry, thus
duplicating mails.

Michael