OK, I have an Microsoft SBS 2008 installation running Exchange. Local Mail send and receive is running fine between all clients. Internet Mail receive shutdown about 15 days ago. Send works fine. Obviously, something changed, but I am not sure what. I have run the BP Scan tool and it says all is well. This has happened a couple of times before when bellsouth/AT&T changed my static IP without warning, but that is not the issue this time. Clients and server all have internet browsing access with DHCP running off the server. We do run our internet mail through a 3rd party server MXToolbox. All is well on their side as well, but their server can no longer send to our server. (all ports closed) I turned the MS Server firewall off and that has not made any difference. I have also confirmed that no settings have changed on my router. The router did have a firmware upgrade in the interim, but I had another without the upgrade and plugged it in and there was no change. Port 25 appears to be closed, but I do not know what to do to open it. I have created a NAT pinhole for mail on port 25 at the router firewall. I have also tried turning the server firewall off. I have also checked the SMTP Exchange connectors; I even created new ones just to see if that helped. Any help would be appreciated. I am completely out of potential solutions on this end.

Open a command prompt on one of your PCs. Type: telnet yourSBSservername 25 Does anything respond?

Telnet from internal client computer: 220 SALTERSERVER.salterlaw.local Microsoft ESMTP MAIL Service ready at Thu, 20 M ay 2010 17:22:01 -0400 Telnet from same client to router static IP: Connecting To 65.13.197.251...Could not open connection to the host, on port 25: Connect failed

Hi Check with www.mxtoolbox.com to see if the traffic goes through Do a SMTP testJonas Andersson MCTS: Microsoft Exchange Server 2010, Configuration | MCITP: EMA | MCSE/MCSA Blog: http://www.testlabs.se/blog

I checked with mxtoolbox and their server cannot connect to my server. We have checked everything on their side and confirmed that the connectors are set up correctly on my server as well. Here is a read on the smtp test. 220 p02c12m063.mxlogic.net ESMTP mxl_mta-6.6.0-0 [5c4b0940.4354659.00-131]; Fri, 21 May 2010 08:07:40 -0600 (MDT); NO UCE, INBOUND Not an open relay. 0 seconds - Good on Connection time 0.250 seconds - Good on Transaction time OK - 208.65.145.13 resolves to mxl145v13.mxlogic.net OK - Reverse DNS matches SMTP Banner Session Transcript : HELO please-read-policy.mxtoolbox.com 250 p02c12m063.mxlogic.net [47 ms] MAIL FROM: <supertool@mxtoolbox.com> 250 Sender Ok [47 ms] RCPT TO: <test@example.com> 451 Could not load DRD for domain (example.com) rcpt (test@example.com) [109 ms] QUIT 221 p02c12m063.mxlogic.net Service closing transmission channel [4354659.00] [47 ms]

The error “Could not load DRD for domain” means a failed relay, which seems that the MXLogic doesn’t put your SBS server into their relay list The error could also cause by misconfiguration in the NATJames Luo TechNet Subscriber Support (http://technet.microsoft.com/en-us/subscriptions/ms788697.aspx) If you have any feedback on our support, please contact tngfb@microsoft.com

Thanks, James. You put me on the right track. The problem was my NAT pinhole configuration on the Motorola Netopia Router 3347. The problem was initially caused by an upgrade to the router firmware. I did switch to another router without the firmware upgrade, but it did not have the Port 25 pinhole setup either. I thought that I had set up the NAT pinhole correctly on the new router, but I found out from Motorola support that I had not. Once I configured the pinhole correctly, the port opened and mail flowed freely.

Cool! Glad you solved it : )James Luo TechNet Subscriber Support (http://technet.microsoft.com/en-us/subscriptions/ms788697.aspx) If you have any feedback on our support, please contact tngfb@microsoft.com