Hello, We have three Exchange 2010 servers. Server1 is a DC. Server1 was also Mailbox,CAS,Hub transport and UM. Server3 is a new server and it's also Mailbox,CAS,Hub transport and UM. In order to remove exchange server from server1 (the DC), I was uninstalling exchange roles one by one. I have uninstalled UM and Hub trasport roles till now. After Hub transport removal, mailbox users became not receiving emails. What did I miss? I have ensured that the default receive connector is configured well and allowing anonymous senders. Also I have forwarded the inbound SMTP traffic (TCP:25) from the external Internet to Server3. By the way, I have checked the receive log on Server3. I found that some messages (which have been sent before hub transport removal and received by recepient) have this line in the log, which is not present in new messages: 2011-05-26T01:54:16.589Z 192.168.1.55 RMExchange2 192.168.1.50 DC.ourdomain.com 08CDE92B92B2D6EA;250 2.6.0 <000901cc1b47$0ce73a10$26b5ae30$@sender.net> [InternalId=3] Queued mail for delivery Intra-Organization SMTP Send Connector SMTP SEND 12 <000901cc1b47$0ce73a10$26b5ae30$@sender.net> recepient@ourdomain.com 250 2.1.5 Recipient OK 4306 1 test message sender@sender.net sender@sender.net 2011-05-26T01:54:14.810Z;LSRV=RMExchange2.ourdomain.com:TOTAL=1|SMR=1 Incoming At last I have to completely remove the exchange from DC. So I need help in solving this without having to reinstall hub transport role on DC. Your early help is highly appreciated.

What are the roles on Server 2? Do you have a send connector that has server 3 specified as source server? Run MailFlow troubleshooter & share the result please.Regards, Pushkal MishrA

Thank you, Server2 also has Mailbox, CAS, Hub transport and UM. It also should be removed later. Finally, we will have only Server3 as an Exchange server in our organization. The only send connector in the organization has RMExchange2 as the source server. I have found the following error and warning when running MailflowTroublshooter: Error: Mail submission failed: Error message: The SMTP host was not specified Warning: Exchange Server is not capable of supporting Internet Protocol Version 6 (IPv6) addresses on server RMExchange2. An IPv6 address was found on adapter '[00000007] D-Link DGE-528T Gigabit Ethernet Adapter'

Hi! When I recieve strange errors the first thing I do is to do some Exchange BPA scans to get som clues of what is going on. For The error message look at this link: http://movement3.wordpress.com/2010/05/12/exchange-2010-the-smtp-host-was-not-specified/ Hopefully it can help you. For the Warning have a look at this link: http://social.technet.microsoft.com/Forums/en-US/exchange2010/thread/1de08c4c-8a54-4545-b962-25f28b30379e Qoute: "For now, IPv6 is supported only when IPv4 is also used. Please check the latest information here" Regards

Ok ...Now,Remove the IPv6 IP address range (Local IP address and Remote IP Address) from both the receive (Default and Client) connectors & make sure on default Receive connector(s) has authentication method set as “Exchange Server Authentication” Restart the Transport service Test the mailflow and let us know the result if negative, then run Mailflow troubleshooter again and share the result please. Regards, Pushkal MishrA

Hi Error: Mail submission failed: Error message: The SMTP host was not specified Do you open smtp port ? It seems to be that the IP of that system or even FQDN is in your block list kindly check with message tracking also check event viewer and post here if there is any error. 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.

Thank you for the post ! It worked. I have done the following in order to solve the problem: 1. Removed the IPv6 address from both (default and client) receive connectors. 2. Disabled IPv6 from both servers NICs Also I noticed that the DC is overloaded because of a huge Exchange mailbox database on it. This is still causing some delay in delivering messages. I will uninstall Exchange from the DC after moving all Mailboxes.

You're welcome.Regards, Pushkal MishrA