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cannot telnet to port 110

Hi. today we started having problems emailing from our office. We all use pop email.  We were getting an error message in outlook saying it could not connect to the incoming mail server. I contacted our mail host who said it was an issue with our isp who did not have an rdns entry for our ip address. I contacted our isp who said they do not setup rdns on dynamic addresses. So I am confused. For a test I attempted to telnet to our mail host and could not at the office but could at home (different isp). I can also telnet on port 110 to several other mail server without a problem from the office. Can anyone shed some light on this for me? Or perhaps give me an idea what other tests I can do to try and confirm where the problem really lies?

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Dave Baldwin
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Are you unable to telnet to that server both by IP and FQDN?
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I went to the shields up site and ran the test on all service ports which showed all ports were "stealth".

I am unable to telnet by both ip and fqdn.
That's may not be good.  What is working at work?  Do you have a router with firewall?  Do you know anyone else with this ISP that can run the Shields Up test also so you can compare results?
I ran the shields up test on another client with the same isp. The results were different, with a number of ports including 110 not showing stealth.
So your task now is to find out what is blocking your ports at work.  How are your computer configured?  Do you have a Windows server network or just a peer network?  What do you go thru to connect to the internet?  Is anything still working?
Thanks Dave, things are working again. It was definitly the isp. I reset the adsl modem and router and recieved a different address which works on port port 110. I am recommending to the client to move to a different isp. I talked to two seperate techs at the isp yesterday who were no help whatsoever. You would think they could have at least suggested restarting the modem to get another address. I don't know maybe I should have thought of that.
Glad you got it working.  In a lot of places, the people who answer the tech support line are just phone answerers with scripts and not much tech knowledge.  That makes it more of a do-it-yourself thing unless you can get it escalated.

ADSL modems that I have used and dealt with seem to be very susceptible to brownouts screwing up their operation without showing any errors.  So anytime your internet access seems to suddenly act differently, keep your modem in mind.  I would also ask your ISP if they offer a fixed IP option.  I have always had a fixed IP so I could use remote mail servers on all the web sites I maintain.  It used to be a requirement with my ISP.