Exch 2003 - Hotmail items stuck as "queued" in SMTP connector

New SBS 2003 R2 SP2, w/ Exch 2003 installation (SP2). All mail gets routed and queued correctly except to Hotmail. Mail to any Hotmail account usually sits in the SmallBusiness SMTP Connector Hotmail queue as “Queued” with “0” retries for anywhere from 40 minutes to 12 hours. Other items queue up behind it and then all send successfully at random intervals and are sent successfully.

Also, the queue icon is a plain folder with no “circle” indicating a status (such as check mark or arrow)

Maximum logging and wireshark sniffing show no attempt to contact Hotmail when the item is queued. It just sits there.

We’ve :

-      Installed and run the Exchange BP Analyzer (no issues found)
-      Manually connected to Hotmail SMTP via telnet with no issues
-      Verified DNS and SMTP through the firewall successfully
-      Run DNSStuff reports against the domain (reverse DNS issue identified and resolved 5 days ago)

The only thing that tools show as an issue is a blacklisting with Backscatter (but NDR reports have been turned off). If this were an issue though, wouldn’t I see retries and failures?

AV/Anti-Spam is Symantec Information Mail Security
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Alan HardistyConnect With a Mentor Co-OwnerCommented:
A backscatter listing advises me that you are sending out NDR reports to invalid recipients.  Please have a read of my article and check your configuration:
http://www.experts-exchange.com/articles/Software/Server_Software/Email_Servers/Exchange/How-to-prevent-Spoofed-Emails-in-Exchange-2003.html 
Turning off NDR reports is not advisable - Filtering Invalid Recipients (if this is your only Exchange Server and your mail is delivered directly to your SBS box) is the best method to combat Backscatter.
Is the listing a current listing?
Hotmail also list people for no seemingly good reason, but getting yourself off the Backscatter site would be my first suggestion, then tackle Hotmail if the problem persists.
An alternative, it to set up a new SMTP COnnector to route Hotmail emails via your ISP's mail server instead of sending it directly.
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TechShelfAuthor Commented:
Thank you, that's very good into and we did check all items but still no luck. I did another wireshark capture last night and I'm seeing TCP Lost Segment acks to Hotmail and one other MX host. We're going through a TZ 180 firewall. I would think that these could be the issue as well.
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Alan HardistyConnect With a Mentor Co-OwnerCommented:
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TechShelfAuthor Commented:
This did not resolve the issue. it's still a problem.
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Glen KnightCommented:
This question has been classified as abandoned and is being closed as part of the Cleanup Program.  See my comment at the end of the question for more details.
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