Neohapsis is currently accepting applications for employment. For more information, please visit our website www.neohapsis.com or email firstname.lastname@example.org
From: Mike Abraham (Mabrahamconestogac.on.ca)
Date: Wed Apr 02 2008 - 12:52:59 CDT
Thank you for the response.
While this does describe the result, it is not the cause. I have come across this page several times.
It seems to be caused by the PIX firewall.
As soon as they turn off SMTP FIXUP PROTOCOL, it starts working fine.
I can't seem to convince everyone to turn off the FIXUP MAILGUARD function, so I need a Postfix workaround.
>>> On 4/2/2008 at 1:31 PM, mouss <moussnetoyen.net> wrote:
Mike Abraham wrote:
> Am I ever glad I found this postfix group. I hope someone can help with
> this problem ?
> We are currently running postfix v2.2.10 with MAIA for Spam filtering.
> When some remote sites attempt to send email to us, they receive the
> There was a SMTP communication problem with the recipient's email server.
> Please contact your system administrator.
> <EXCHANGE.Bluedrop.local #5.5.0 smtp;500 Non RFC-compliant response received>
does this apply?
> It always seems to be the sender has a EXCHANGE / PIX combination.
> The log produced from DEBUG_PEER on my POSTFIX server simply shows the peer
suddenly drops the SMTP session for no reason.
> Has anyone found a solution or similiar situation with PIX firewalls causing
a "Non RFC-compliant" error ?????
> Is there a workaround other can forcing the sender to disable SMTP FIXUP
PROTOCOL on the PIX ? They don't always
> like this. Some admins refuse, saying it's our problem. Not there's.