I have been working on a test server with a /29 and it had been working smoothly with 2 domains.

I then moved the server onto a new set of IP Range being a /28 holding all configs the same.

However since changing the IP on the Hyper-V Host to the new range - Exchange 2013 has stopped sending emails out and throwing the following error:

EXCH1.test.local rejected your message to the following email addresses:
z***r@gmail.com (z***r@gmail.com)
EXCH1.test.local gave this error:
Unable to relay 

Your message wasn't delivered due to a permission or security issue. It may have been rejected by a moderator, the address may only accept email from certain senders, or another restriction may be preventing delivery.

Diagnostic information for administrators:
Generating server: EXCH1.test.local
z***r@gmail.com
EXCH1.test.local
Remote Server returned '550 5.7.1 Unable to relay'

NOTE: I have not changed anything apart from the PUBLIC IP. Internal IP is 192.168.18.20 and this had not changed. Receiving emails from anywhere is not a problem. Server is single multi-role server.

Here is the Transport Agents:

[PS] C:\Windows\system32>Get-TransportAgent

Identity                                           Enabled         Priority
--------                                           -------         --------
Transport Rule Agent                               True            1
Malware Agent                                      False           2
Text Messaging Routing Agent                       True            3
Text Messaging Delivery Agent                      True            4

Here is the Receive Connectors:

[PS] C:\Windows\system32>Get-ReceiveConnector

Identity                                Bindings                                Enabled
--------                                --------                                -------
EXCH1\Client Proxy EXCH1       		{[::]:465, 0.0.0.0:465}                 True
EXCH1\Outbound Proxy Frontend EXCH1 	{[::]:717, 0.0.0.0:717}                 True
EXCH1\Client Frontend EXCH1     	{[::]:587, 0.0.0.0:587}                 True
EXCH1\Default Frontend EXCH1    	{0.0.0.0:25}                            True
EXCH1\Default EXCH1             	{0.0.0.0:2525}                          True

Default Frontend - not changed (TLS, mutTLS, Basic, BasicTLS, Integrated, ExServer - ExchSvr,LegExchSvr, Anon) - scoped * port 25

Default - not changed (same as above, but ExchUsers instead of Anon) - scope 192.168.18.0/24 port 2525

I am sure this is so simple, however I cannot get my head around why it is rejecting outbound emails to any domain outside the org.

I have tried creating a new Receive Connector pure for Anon for internal exchange server however resulted in the same even with the following command:

[PS] C:\Windows\system32>Get-ReceiveConnector "Outbound Relay for Internal" | Add-ADPermission -User 'NT AUTHORITY\Anony
mous Logon' -ExtendedRights MS-Exch-SMTP-Accept-Any-Recipient

Here is the Send Connector for reference and sends via MX directly:

[PS] C:\Windows\system32>Get-SendConnector

Identity                                AddressSpaces                           Enabled
--------                                -------------                           -------
Send Connector                          {SMTP:*;1}                              True

I have tried deleting the Send Connector and the latter 2x Receive Connectors without any change. Have restarted the server and Transport Service after making changes.

Any help would be greatly appreciated.

 One thing that is strange is that I cannot telnet to any SMTP outside as it is always being accepted by EXCH1 constantly - not sure if this has anything to do with it!

• Edited by InexperiencedPorkRoll Tuesday, April 14, 2015 3:24 PM

Send connectors determine routing for all mail from an Exchange server to recipients outside the Exchange organization.  OWA clients don't send via SMTP, it submits it to the store, so there is no receive connector involved in sending mail