How to open port 110 on SBS

Dear experts,

I have a problem with POP3 connector and am desperate to get a solution fast.

Basically the POP3 connectors on SBS server no longer retrieve email from external mail server. There are a lot of errors in the event log. In order to get emails I have setup local POP3 account on Outlook for each user, and that has been working fine.

I did some basic test on the server and find that I cannot TELNET our mail server. I can ping the pop server and has internet access but just can't use TELNET. In general there is no respond after I type "Telnet pop_server 110"; I have tried BOTH name and IP address of the external pop server.

I am not able to test this on client laptop because it is a client. However, I know the mail server is up and running because they are getting emails via Outlook and I can telnet port 110 of their mail server from my office. So it seems that the server itself is blocking port110 traffic (users are getting email from Outlook so I can't see the problem is with the router).

Can anyone plase tell me how to test if port110 has been blocked on the server, and utimately how to reopen it? I have checked TCP/IP filter (single NIC) has not been enabled.

This is urgent. They have a couple of off site workers who use OWA, and that has stopped working.

Thanks in advance.

LVL 23
ormerodrutterAsked:
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andrew_aj1Commented:
Here are two good sites to check if certain ports are open:
http://www.t1shopper.com/tools/port-scanner/
 http://whatsmyip.org/ports/
Do you have a router? It may have to setup port forwarding on that too, not just making sure the windows firewall is not blocking it.
I hope this helps. Good luck.
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ormerodrutterAuthor Commented:
Tried both utilities and result says port 110 is open on the server.

So why is it not retrieving email? The mail server is up and running because users are getting email in Outlook. Also, why Telnet doesn't work?
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andrew_aj1Commented:
You stated that your pop3 connector on SBS no longer retrieve email from the server. Is the service running for this? If so you may want to check your settings - it may require ssl to be turned on or off and you have it set wrong. You may also want to test the connector with a different pop3 account hosted somewhere else.
Hopefully this will help you. Good luck.
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ormerodrutterAuthor Commented:
No it is definitely NOT SSL - I knew that because I set users up on their Outlook. I have also downloaded and installed a third party POP3 utility and that fails too. So I am pretty sure its something wrong with the server.
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andrew_aj1Commented:
Is the connector service running? Can you test this with a different pop3 server?
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ormerodrutterAuthor Commented:
I have already tried with another pop3 mail server. Same result.
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andrew_aj1Commented:
Is the connector service running correctly?
Do you have any errors in the event viewer?
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Lee W, MVPTechnology and Business Process AdvisorCommented:
The POP3 Connector is used to download mail from an ISP hosting your e-mail and distribute it to your exchange accounts.  Since the connection is initiated from the server, there should be no problem unless you are running a third party firewall product (hardware/software) and have explicitly blocked port 110 from your clients/system.

OWA does NOT use POP3.  If these clients are using OWA, then Port 110 is STILL not used - OWA uses port 80 and/or 443 (SSL).

I would suggest verifying that port 25 is open to and from your server and verify that the ISP hasn't blocked port 25.  I had that problem at one client and had to use an alternate port number or have the ISP unblock port 25.
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ormerodrutterAuthor Commented:
leew,

Thanks for your suggestion. I thought port 25 is used for sending (smtp) email and port 110 for receiving? Sending is no problem and clients are able to send through Exchange so I don't think port25 is blocked, but I will certainly check again.

I know about port 443 for OWA - the issue is that OWA users can't get "new" email.

In the mean time I will unintall the AV software to see if that makes a difference.
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ormerodrutterAuthor Commented:
I have found the reason and solution.

It was the AV software that blocks the port. Its AVG v8 - I went in and disable the Email Scanner and thing works straightaway. However I don't see a way to get in AVG firewall for port opening. So I will leave the Email Scanner disabled, or perhaps I will reinstall v7.5, that we know there isn't an issue.

Thanks for your input guys. Very much appreciated.
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Lee W, MVPTechnology and Business Process AdvisorCommented:
Depends on how your e-mail is setup - server to server, port 25 is used.  server to client, port 110 (for POP3) is used.
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