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bookem
04-09-2009, 08:38 PM
I know this may not be the best place to post this, but I've been trying to track this down all day and hopefully somebody here can help...

I've got an Exchange 2007 (Version 8.1 (Build 240.6)) installation as part SBS 2008 Premium. On a separate machine, I have an asterisk VOIP server handling my incoming faxes. Prior to making the switch to Exchange, the VOIP server was successfully receiving faxes and sending emails with PDF attachments, and since the move to Exchange the emails are coming through with no attachments. No configuration on the VOIP server has changed except for the SMTP relay server now being Exchange instead of our ISP.


Here is an example header before the move to Exchange (domain names changed to protect the innocent):

Received: by asterisk1 (sSMTP sendmail emulation); Wed, 08 Apr 2009 09:58:45 -0600
Date: Wed, 08 Apr 2009 09:58:45 -0600
From: HylaFAX Agent <fax>
To: [email protected]
Subject: Fax received from "EsyncMailfaxPlus"
Mime-Version: 1.0
Content-Type: Multipart/Mixed;Boundary="NextPart1605"
X-SCA-Stop: [B6A0F3C6EF4D431D877402DC88784B1A,7,16,0]
Message-Id: <[email protected]>
Envelope-To: [email protected]


Here is the header after the move:

Received: by asterisk1 (sSMTP sendmail emulation); Thu, 09 Apr 2009
17:08:54 -0600
Date: Thu, 9 Apr 2009 17:08:54 -0600
From: HylaFAX Agent <fax>
To: FaxMaster
Subject: Fax received from "Fax Sender"
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: Quoted-Printable
Message-ID: <[email protected]>
Return-Path: [email protected]
X-MS-Exchange-Organization-Antispam-Report: IPOnAllowList
X-MS-Exchange-Organization-SCL: -1
X-Auto-Response-Suppress: DR, OOF, AutoReply

A couple notes on the configuration:
-Because the VOIP server is sending anonymously, I've added it's IP to the range specified in the "Internet Receive" connector rather than add "Anonymous Users" to my Default receive connector.
-The VOIP server's IP is on the Anti-Spam IP Allow List
-The recipient [email protected] is a distribution group that does not require that all senders are authenticated

My guess is that Exchange has decided to fudge the content-type header and thus removes the PDF attachment, but I have no idea why. Here's what I've tried so far to fix the problem:
-Created a transport rule to change the content-type header back to multipart/mixed: No Success
-Set the "Exchange rich-test format" option to "Never use" for all Remote Domains: No Success
-Changed my Content Filtering SCL threshold for rejecting messages to 8 instead of the default 7: No Success


What am I missing? Is there any way to actually see what Exchange is doing to my message?

Thanks,
Dan

whoatemyling
04-11-2009, 11:59 AM
what are the size of the PDF's?

is there an attachment size limit on your exchange server?

bookem
04-11-2009, 11:01 PM
The PDF's are usually about 20K, and my email size limit is about 30M.

SpireTECH
04-13-2009, 12:03 AM
As you've already guessed, the reason the attachment is not coming through is that the content-type is getting messed up.

There can be a number of reasons this is happening. The first step is to run a packet sniffer on one of the servers and determine if it's the MTA on the asterisk server which has specified this content type, or if the Exchange server is messing it up.

Zhariak
04-17-2009, 10:42 AM
Not enough Jigawatts,

I just recently migrated a few servers from 03, to 07... And wow, what a pain...

Anyways...

With SBS, there is a section in the config regarding automaticly removing attachments. I think by default it is enabled (even though PDFs shoudln't be inside the list).

I think what I mentioned above, is prompted when you first configure the e-mail wizard for SBS.


Also, if you took advantage of the Microsoft Anti-Virus/Malware stuff, that could also be causing the pdfs to get removed. With all my clients I don't bother with the trials of the security software (as I prefer the Symantec Multi-tier suite).

Check into both things I mentioned above. I'm curious to see if it fixes up your problems.

bookem
04-17-2009, 06:47 PM
What we ended up doing was going to an external fax->PDF service (the fax # migration hasn't happened yet, though) so hopefully that resolves the issue.

Regarding the possible solutions posted above:


The first step is to run a packet sniffer ...
Haven't tried a packet sniffer yet, and with the move to the external service I don't think I will bother, but a great suggestion (though I was hoping it wouldn't come down to this). The reason I left this was because the emails were being received OK prior to the move to Exchange, leading me to believe the problem is solely Exchange.



With SBS, there is a section in the config regarding automatically removing attachments ...
I believe this is the case with SBS '03, but I don't recall seeing it in SBS '08... I think it was repackaged as a Forefront technology.


Also, if you took advantage of the Microsoft Anti-Virus/Malware stuff ...
I didn't, and to be honest I don't know if I will bother with any AV/AM on the server... desktop clients installed all around, and by all around I mean on both clients so it's just as easy to administer 2 clients from the desktop environment.

Thanks for looking guys, I will post the results of the fax migration once it happens.

Zhariak
04-17-2009, 07:01 PM
Originally posted by bookem
What we ended up doing was going to an external fax-&gt;PDF service (the fax # migration hasn't happened yet, though) so hopefully that resolves the issue.

Regarding the possible solutions posted above:


Haven't tried a packet sniffer yet, and with the move to the external service I don't think I will bother, but a great suggestion (though I was hoping it wouldn't come down to this). The reason I left this was because the emails were being received OK prior to the move to Exchange, leading me to believe the problem is solely Exchange.



I believe this is the case with SBS '03, but I don't recall seeing it in SBS '08... I think it was repackaged as a Forefront technology.


I didn't, and to be honest I don't know if I will bother with any AV/AM on the server... desktop clients installed all around, and by all around I mean on both clients so it's just as easy to administer 2 clients from the desktop environment.

Thanks for looking guys, I will post the results of the fax migration once it happens.

The attachment filtering wasn't re-badged... It is a part of the SBS 08 config...

If forefront is on your server, check that. Wouldn't be surprised if that was playing part.

bookem
04-18-2009, 05:46 PM
Originally posted by Zhariak


The attachment filtering wasn't re-badged... It is a part of the SBS 08 config...

If forefront is on your server, check that. Wouldn't be surprised if that was playing part.

I don't have Forefront... I must have missed that setting in the config, can you direct me to it?

Zhariak
04-19-2009, 10:47 AM
Originally posted by bookem


I don't have Forefront... I must have missed that setting in the config, can you direct me to it?

Argh, uhhh... I can't remember where it is, unfortunately I dont have any Dev environments setup right now, all the SBS boxes I have access to are in production...

Just goto the SBS Console (Advanced, I donno if it makes a difference). And run the e-mail configuration wizard.

Let me know how it turns out.

SpireTECH
04-20-2009, 12:41 PM
Originally posted by bookem
... leading me to believe the problem is solely Exchange.

I would agree, that is the most likely suspect. But I'm also painfully familiar with the process of trying to interface RFC compliant software with any sporting the MS logo. A simple change in syntax between 2003 and 2007 could easily cause this whole mess.

bookem
04-29-2009, 07:49 AM
So to wrap this up...
I never found the attachment filtering options... Google suggests that it was moved to Forefront, which I do not have installed.

I ended up using MS Network Monitor to try and diagnose the problem, but the logs from Netmon showed the same information as the SMTP logs. I suspect that MS Exchange was the problem but I have no proof that it was, or that the asterisk server was sending any wrong headers, or that there was any non-compliance on either end.

In the interest of having a working solution, we changed the settings on the asterisk server to point back to the ISP's SMTP relay, and now the emails and attachment come in without issue. :dunno:

Zhariak
04-29-2009, 09:53 AM
Originally posted by bookem
So to wrap this up...
I never found the attachment filtering options... Google suggests that it was moved to Forefront, which I do not have installed.

I ended up using MS Network Monitor to try and diagnose the problem, but the logs from Netmon showed the same information as the SMTP logs. I suspect that MS Exchange was the problem but I have no proof that it was, or that the asterisk server was sending any wrong headers, or that there was any non-compliance on either end.

In the interest of having a working solution, we changed the settings on the asterisk server to point back to the ISP's SMTP relay, and now the emails and attachment come in without issue. :dunno:

Hmm, atleast it's fixed! That's the important thing.

How many users do you have on your asterisk setup just curious (totally offtopic)? How's it working out?

bookem
04-29-2009, 09:36 PM
Originally posted by Zhariak

How many users do you have on your asterisk setup just curious (totally offtopic)? How's it working out?

There are only 2 users in the home office setup, but there are 4 phones operating 3 lines and a fax through the server. They used an old desktop box and put in a cheap pentium mobile processor I think (the box is pretty much silent now). It works pretty slick... have voicemail to email, remote patching to skype phone for free calls during international travel, etc. I'm not the guy who set up that asterisk system, so I don't know all the deets on time and cost.

Zhariak
04-30-2009, 07:31 AM
Oh...

nice setup...

One big issue I've had is getting the faxes going, but thats because of my businesses VoIP provider. Upgrading to a PRI here pretty soon.

I love asterisk :) I've got a Trixbox setup, with a few SIP trunks to other asterisk boxes, and a Cisco Unified Call Manager server. Works like a charm.

The only thing I have to figure out is how to have trixbox handle voicemail for the phones on the Cisco server.