SBS 2008 POP3 Connector on Exchange 2007 - Timeout during mail delivery

A customer has been using the built-in POP3 Connector to collect some external accounts, bringing them in to the selected users.  It is a very small company & there is no SMTP inbound used.  The POP3 Connector has been running happily for several months - since they purchased the new server with it.  Recently they were disconnected from the Internet via hardware fault and were without access for a week.  The server is now back on line & experiences issues with the collection of the e-mails - sending continues to work.

Having been through the blog article on Technet, the crucial symptom I have pinned down is an Event 208: Timeout on the SMTP delivery side (POP3 Connector sending into the server via localhost:25).

"Event 208: The TCP/IP Connection with the 'localhost' server was terminated while trying to access the '<mailbox>' mailbox.  The cause may be server problems, a long period of inactivity, a connection time limit, or incorrect connection settings."

Having turned on verbose logging on the POP3 Connector, I can confirm the symptom of sending the e-mail in (DATA exchange of SMTP delivery) completes as follows:

"[t 0] 11/19/10, 15:09:55: (SMTP) [TX]
[t 0] 11/19/10, 15:10:35: Timeout 'localhost' !!!!
[t 0] 11/19/10, 15:10:35: Failure hrResult (0x800ccc19) trying to deliver message id 2:
[t 0] 11/19/10, 15:10:35: (no server response)
[t 0] 11/19/10, 15:10:35: EVENT: The TCP/IP connection with the 'localhost' server was terminated with while trying to access the '' mailbox.  The cause may be server problems, network problems, a long period of inactivity, a connection time limit, or incorrect connection settings.
[t 0] 11/19/10, 15:10:35: (AsyncConn [ localhost:25 ]) Connection to 'localhost' closed."

I can telnet to localhost:25 and send an e-mail manually - even delaying the conversation for longer than it takes for a "Retrieve Now" on the POP3 Connector to fail (i.e., start telnet session with localhost:25, EHLO, MAIL FROM, RCPT TO, DATA, start the Retrieve Now on the POP3 Connector and wait for it to fail, back at the telnet session complete the E-mail detail and finish with the . on a line by itself & the telnet e-mail is accepted).

Blog article already gone through with a fine-toothed comb:
Additional EE Q to ensure the timeout is higher than needed: - both the accepted solution & the after-comment.

NB: I do not need any lectures about using the POP3 Connector!  There's a good reason & if you don't agree with its use please simply don't answer.
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BarthaxConnect With a Mentor Author Commented:
I now have successful POP3 transactions on the smallest mailboxes - re-running the "Connect to Internet" wizard has indeed resolved the issue (after disabling DHCP on the router!).  Larger messages are now trickling in.
BarthaxAuthor Commented:
Found and the solution therein was to re-run the "Connect to the Internet" wizard on the Windows SBS Console's Home tab.  This does make sense: the site has a new router & I've discovered the DHCP is enabled on it.  Alas, I haven't the credentials to alter that right now and I've run out of time today... Will be checking this on Monday with the customer.
usually this sort of thing is caused by the volume of mail. I suspect that the pop puller connects to exchange via SMTP to check it can open a connectiom, then asks for a list of mail from the remote pop server.for some rason its not getting this, and the SMTP connection times out.

Can you manually download the mail from the POP server with say out look ad copy it to users mail boxes to see if it is the volume of pending mail thats the problem..
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Alan HardistyCo-OwnerCommented:
This sort of problem can also be caused by corrupt messages - can you view the messages on the remote server and see if there are any junk emails you don't want, then delete them and then kick off a POP collection.  Does it complete?

Is there any reason for still collecting via POP3?  SMTP Delivery if much easier and less problematical.
BarthaxAuthor Commented:
Thanks for the responses.  The POP3 mailboxes are fine & can be downloaded directly with a POP3 client.  I've already resolved typical POP3 Connector issues (event IDs 217 - Invalid headers & 210 - message left due to size) with other sites and the usual tactics were tried here: disable all but one mailbox (that with the smallest e-mail load), reduce the permitted size via the Windows Fax Hub down to the minimum 64KB & get all the small messages in, then steadily add mailboxes until they're all active & then steadily increase the permitted message size to the desired maximum... Trouble is, with even the smallest mailbox (only 3 messages, all are <5KB) the SMTP delivery connection from POP3 Connector to Exchange Transport gets dropped as soon as the delivery _into_ Exchange is attempted.  With the POP3 Connector on verbose logging, I know this problem isn't the POP3 mailbox.

I'm just about to re-run the "Configure Internet" option of SBS Console due to the new router.

> Is there any reason for still collecting via POP3?  SMTP Delivery if much easier and less problematical.
SMTP and POP3 both have their desired results & the customer is not concerned with having their own domain.  POP3 mailboxes suit the customer.  It has taken more than a decade to convince them to change their server...  E-mail "working the way it always has" isn't about to be changed.
BarthaxAuthor Commented:
Stumbled across another Q with solution.
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