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SBS 2003, Exchange SMTP outgoing queues stuck just on some domains.

hlieberman
hlieberman asked
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Last Modified: 2012-05-06
SBS 2003, Exchange SMTP outgoing queues stuck just on some domains.  reverse dns okay, not on blacklists, no errors, other than sending back a delay message back to internal sender.   Was working fine, then this just occurred.
Comment
Watch Question

Do the messages eventually get sent after a delay?

Since you are saying that it only happens on particular domains, Is it possible that some of the problem servers are greylisting?

http://www.greylisting.org/

Basically, if a recipient server is using greylisting, it works by initially rejecting the first message from a sender it has never seen before.  
Most legit mail servers are configured to re-send the message after a couple of minutes.
Most spam servers or zombie hosts do not conform to the standard smtp practices, and will not send a retry message.  

Author

Commented:
No, this started happening today. The server has been in operation for several years.  Many of this client's - clients emails, that previously went through with no problem, plus public domains are being randomly "Stuck" in Queue.    There is a "you do no have to resend this message - delayed" message returned to the internal sender eventually,  But they seem to just stay stuck in retry mode in the queue.
Expert of the Quarter 2009
Expert of the Year 2009

Commented:
If you click on the queue, what reason code does it give?

-M

Author

Commented:
I had cleared all of the queues to see if it was a jammed message causing it.   This was about at the close of business there today.   There are only three queues there at the moment with retries.  One says "The specified network name is no longer available.", another says "An SMTP protocol error occurred.", the third says "The remote server did not respond to a connection attempt." /...

Author

Commented:
Running SMTP diag tool on rejected email recipients returns "Error: Expected "220". Server is not accepting connections.  Failed to submit mail to person@emailaddress.com"
Expert of the Quarter 2009
Expert of the Year 2009

Commented:
That either means the server isn't responding or there is a routing issue.
You could use a third party tool to test the server to see if it is responding. If it fails on that test then the problem isn't with you.

-M

Author

Commented:
It can't be that so many recipient's servers are not responding all of a sudden.   This just happened to a functioning server starting yesterday.   Many other emails go through to other domains.   It's just a mix of what appear to be random domains where the queue remains stuck in the retry mode.  It's acting as if iit's a blacklist type thing, but the ip address does not appear to be on any blacklist that I can find.
Expert of the Quarter 2009
Expert of the Year 2009

Commented:
If it was a routing issue, then it would affect lots of domains. You need do a tracert to the MX record host and see if it dies somewhere.

-M

Author

Commented:
Doesn't appear to.   Here's a tracert to one of the affected domains....

tracert inbound.pirsch-law.net.netsolmail.net

Tracing route to inbound.pirsch-law.net.netsolmail.net [205.178.149.7]
over a maximum of 30 hops:

  1    <1 ms    <1 ms    <1 ms  10.0.0.1
  2    <1 ms    <1 ms    <1 ms  h-66-134-38-33.mclnva23.covad.net [66.134.38.33]

  3     8 ms     9 ms    11 ms  172.22.0.1
  4    13 ms     9 ms    10 ms  192.168.22.13
  5    12 ms     9 ms    10 ms  192.168.253.90
  6    13 ms     9 ms    10 ms  207.88.183.133.ptr.us.xo.net [207.88.183.133]
  7    12 ms    10 ms    10 ms  65.106.3.185.ptr.us.xo.net [65.106.3.185]
  8    11 ms    12 ms    10 ms  207.88.183.30.ptr.us.xo.net [207.88.183.30]
  9    16 ms    15 ms    15 ms  edg-r-01-vlan10.net.dc2.netsol.com [205.178.191.
2]
 10    15 ms    15 ms    15 ms  205.178.182.6
 11    11 ms    15 ms    10 ms  mail.networksolutionsemail.com [205.178.149.7]

Trace complete.
Expert of the Quarter 2009
Expert of the Year 2009

Commented:
What is between the Exchange server and the internet?

-M

Author

Commented:
A Linksys RV042 vpn Router...
Expert of the Quarter 2009
Expert of the Year 2009

Commented:
You have to start looking at other things - antivirus on the server for example.

-M
Even though the server's ip address did not show up on any blacklists that I could find, using mxtoolbox.com lookup, among others.   I did eventually receive an NDR from "Barracuda Central" indicating that it was on their blacklist.   Never heard of them, and don't see them included in blacklist searches.   I requested removal, but continue to hace similar problems on a smaller scale.   Change ip address of server, hoping that this will get around this issue.

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