During an upgrade of an Exchange 2013 SP1 multi-role server to Exchange 2013 CU8 the upgrade crashed, apparantly on a strange Receive Connector configuration since the following error message was raised:
The values that you specified for the Bindings and RemoteIPRanges parameters conflict with the settings on Receive connector ” SERVER1\Relay Connector SERVER1″. Receive connectors assigned to different Transport roles on a single server must listen on unique local IP address & port bindings.

I didn’t check the Receive Connector configuration although I noted in Server Manager the presence of multiple IP addresses. I never check this since I never ran into this issue, and multiple IP addresses on an Exchange Server typically don’t cause upgrade errors if configured properly.

This server was part of a Database Availability Group, so I tried to open ECP on the second Exchange server to check the configuration, but I was unlucky

The Exchange Management Shell did work… When running the Get-ReceiveConnector –Server SERVER1 command all Receive Connectors on this particular server were shown (although the SERVER1 was broken at this point this information was retrieved from Active Directory).

Obviously the same IP address and port number were bound to different Receive Connectors, a configuration that seemed to be possible to configure in earlier builds of Exchange Server 2013. After removing the “SERVER1\Secure SMTP” and “SERVER1\Relay Connector SERVER1” the upgrade finished successfully.

This issue is not particularly related to CU8 but colleagues have seen this happen with CU6 and CU7 as well and as stated in the previous paragraph, this is a flaw in earlier builds of Exchange 2013.

If you happen to have only one Exchange 2013 you’re in trouble since you don’t have an Exchange Management Shell on another server so you have to work with ADSIEdit to accomplish this. Exchange Server MVP Paul Cunningham wrote about this issue as well and included the steps needed in ADSIEdit: http://exchangeserverpro.com/exchange-server-2013-upgrade-fails-due-to-receive-connector-conflicts/

Fellow Exchange server MVP and MCM Andrew Higginbotham did a similar write up “Incorrectly Adding New Receive Connector Breaks Exchange 2013 Transport” found on https://exchangemaster.wordpress.com/2014/01/24/incorrectly-adding-new-receive-connector-breaks-exchange-2013-transport/.

Microsoft also wrote a similar knowledgebase article about this “ The front-end Microsoft Exchange Transport service stops and does not restart after you upgrade to Exchange Server 2013 SP1” which be found on https://support.microsoft.com/en-us/kb/2958036

Edited on May 26, 2015. Special thanks to Paul Cunningham for the additional comments.