Hi I had crash on my sbs exchange server. Only thing that was available was AD records. After performing critical recovery. Some of users told me, that some our client can't send to them email. They received message as below. Reporting-MTA: dns;snt0-omc1-s22.snt0.domain.com Received-From-MTA: dns;SNT126-DS19 Arrival-Date: Thu, 13 Oct 2011 04:27:51 -0700 Final-Recipient: rfc822;user@domain2.com Action: failed Status: 5.1.1 Diagnostic-Code: smtp;550 5.1.1 <user@domain2.com>: Recipient address rejected: User unknown in virtual mailbox table One thing that I observed was, that when our client send clean text email it i s delivered properly. But with some attachment they get message as previus. I checked my mx record, and it's correctly. Checking was done by http://mxtoolbox.com/ and nslookup command. New server has new name, and new ip address. If you have any idea, I will be gratefull if you can help me. Best regards Keiishi

Have you amended any firewall rules/NAT that needs to be done. Updated your records if you have PTR records Tested using - https://www.testexchangeconnectivity.com/Sukh

Have you amended any firewall rules/NAT that needs to be done. Updated your records if you have PTR records Tested using - https://www.testexchangeconnectivity.com/Sukh