I tried to change my server from using POP3 connectors, to using the "Direct to server" - via the wizard. Publicly,I changed all the MX records to point to my server from the Internet/Host/DNS side, and configured my firewall to allow incoming port 25. I ran the wizard to change from using Pop3, and pointed it to send the mail directly to my server. After all these changes had been made, I was able to telnet mail.mydomain.com 25 and successfully send a message, which I then successfully received on my mail client. I likewise, could telnet directly to my server via my LAN IP, send a message, and have it properly received. HOWEVER - I couldn't receive mail any other way...from any other mail client. No NDR, no errors reported on either end. Is there a way to troubleshoot this? I enabled logging, but nothing of use showed up in the logs. No NDR is received by the sender (even after several hours), no errors are logged in the event viewer or exchange logs. Any ideas of what I might be missing? (I disabled IMF - just to make sure I wasn't blocking anything) Thanks - any hints on what I could check would be greatly appreciated.

Hi, Have you configured the SMTP Virtual Server correctly also have a look at your firewall I think if you have clear your SMTP Virtual server than maybe firewall is the trouble's place. Also I want to let you know that MX entries will reflect on cloud in 48 hours so wait for some time as well. Regards. Shafaquat AlilM.C.I.T.P Exchange 2007/2010, M.C.I.T.P Windows Server 2008, M.C.T.S OCS Server 2007 R2, URL: http://blog.WhatDoUC.net Phone: +923008210320

Thank you Shafaquat.... I "THINK" I have configured the SMTP Virtual Server correctly (double-checked it on working servers), and I've also checked various info out here on the web, which seems to indicate I've done it correctly....there's always the chance I've missed something though! (They can never take my own falability away from me). Perhaps I didn't wait long enough - the names servers I used in nslookup all kept reporting properly, so perhaps I just rushed it. Thanks for the help! I'll give it another try.

So....how often does an ISP block port 25 for INCOMING traffic? I know a lot of them block port 25 outbound (unless authenticated), but I'm curious as to whether the problem might be my ISP. I fought with this for two days, and still couldn't find anything in logs via the firewall or server...SO, I switched out the firewall for a simple router, port forwarded, tested. Nothing. Changed the SMTP virtual server to port 26 and adjusted the port forward in the router - successful telnet (finally). I changed the SMTP port to 1010 and adjusted the port forward in the router - successful telnet (finally). So, the problem appears to be with port 25. I called my ISP, and was promptly told that they do NOT block incoming port 25. I changed everything back to port 25 - still doesn't work. Outgoing works fine, and I can telnet into the server on port 25 via the LAN without problems. Doesn't this seem to indicate that the ISP is indeed blocking port 25 regardless of what their technician told me? What other possibilities are there? Thanks again for any advice you might offer.

Hi, Yes it seems to be that you are right and port 25 is blocked by your ISP so check with the ISP again I think your problem will be solved with the help you your ISP. Regards. Shafaquat Ali.M.C.I.T.P Exchange 2007/2010, M.C.I.T.P Windows Server 2008, M.C.T.S OCS Server 2007 R2, URL: http://blog.WhatDoUC.net Phone: +923008210320

Hi, You also need to open port 110 for incoming POP3 traffic. Port 25 is for outgoing traffic. Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. Thanks Gen Lin-MSFT