Sep 04 2017 10:35 PM
Sep 04 2017 10:35 PM
We've just installed Exchange server 2016 in an existing Exchange server 2010 environment. We've had an issue where the Default receive connector on the HT servers has been configured to only receive mail from certain servers for some reason, and this was stopping some users from sending mail internally. We fixed this up, but I can't get my head around why the Exchange 2016 got involved in this internal mail flow in the first place. None of the namespace or mailflow cutover has occured yet, only the intitial install of the Exchange servers, so I would have thought that internal mail flow would have been through the Exchange 2010 servers only. If anyone can let me know what happens upon the intitial installation of Exchange 2016 that cuases it to be involved in the internal mail flow, that would be great. some Technet articles describing this would be prefect.
Sep 04 2017 11:57 PM
Sep 04 2017 11:58 PM
Here you can see how the Mail flow and transport work https://technet.microsoft.com/en-us/library/aa996349(v=exchg.160).aspx
Note: If you need to change any o the Connectors, use Front End Transport
Sep 11 2017 12:55 PM
Sep 11 2017 03:54 PM - edited Sep 11 2017 03:55 PM
That is not what we have just experienced. With Exchange 2010 and Exchange 2016 installed in the same site, Exchange 2016 servers were picking up internal to internal messages for local delivery from the Exchange 2010 servers. The only way we noticed this is that the client had played around with the default receive connectors on the Exchange 2010 servers and restricted the remote server IP range, so the new Exchange 2016 servers weren't included. This caused messages to queue on the Exchange 2016 servers until they were allowed on Exchange 2010 receive connectors.
Sep 11 2017 11:29 PM
I believe this is due to shadow queue in Exchange 2010, or Safety Net in Exchange 2016. Exchange will always route an email through another Exchange transport server in the same site to create another copy of the message for backfill if necessary. See https://technet.microsoft.com/en-us/library/dd351027(v=exchg.141).aspx
Sep 14 2017 02:02 PMSolution