Borderware Firewalls and Exchange IMC attachments

Borderware Firewalls and Exchange IMC attachments

Post by Andy Web » Sun, 09 Nov 1997 04:00:00

I've confirmed that this is a problem.  I have done some tests and on
initial analysis it looks like a Borderware problem.  I need to get a
couple more packet captures first though.  It only seems to affect large
attachments (500K and larger), and does not happen every time.

We've had our Exchange server behind BW for about 15 months and never
noticed the problem until Ted brought it up in the BW mailing list.  The
messages all go through eventually, but if you use the normal retry backoff
of (.25, .5, 1, 4) it may take several hours to get through the 2-4 retries

I've changed our retry interval to ".25" for the time being and will
continue testing.


Simpler-Webb, Inc.                           Austin, TX
             "Mauve has more RAM" - Dilbert

> There is a problem sending mail with attachments through the Borderware
> 4.1 firewall from Microsoft exchange server.

> This problem started about the time NT 4.0 went to Service Pack 1

> Microsoft confirmed that they have had customers with this problem.

> A work around for this problem is to shutdown the internal to firewall
> proxy and create a Smtp proxy on port 25 internal to external.

> You would then set the IMC on exchange to use DNS instead of forwarding
> everything to the firewall.

> Mail will come in through the firewall SMTP and go out directly from the
> exchange server via the proxy.

> We have had no other problems with mail server except Borderware's.

> Ted Weldon
> Network Manager
> Medford Clinic


1. Problems with Exchange 5.0 IMC attachments!!!


We're testing MS Exchange 5.0 with the internet mail connector (IMC).
The options are set in the way that mails with attachments are sent as
multipart MIME mails.
The IMC sends out such mails over the internet - however when you try to
read these mails withs the AOL client or T-Online 2.0 client (the mostly
used ISP in germany - the german Telekom (winner of Tour de France ' 97))
the attachments are enclosed in the mail-body!! This is independent from
then mime-type used.
In raw text the MIME emails look ok (on first sight) - but they are
interpreted by several clients in the wrong way...

At the moment we've switched back to the MS-Exchange Client Internet Mail
DLL.because this one works?

Any suggestions???
Any pointers to MS Exchange support - news groups????

Matthias Arnold

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