OK so I found some more details online and decided to take the plunge (after a backup was taken) and my problem is now fixed. Although thank you to the 40 people that atleast looked at my query.
This worked for me, please read, backup and decide yourself if you wish to follow my steps.
1. I Read this to understand more on how I broke it in the first place :
First section of this......
https://exchangemaster.wordpress.com/tag/smtp/
then
http://support.microsoft.com/kb/2958036
2. Deleted the Default Frontend "servername" Receive connector
3. Recreated it using these guidelines below. (I included them all for your ref). Source https://social.technet.microsoft.com/Forums/exchange/en-US/32e13998-a84e-4f10-8557-3f7ce6fdb824/2013-default-receive-connectors:
[PS] C:\>Get-ReceiveConnector | fl Name,AuthMechanism,RemoteIPRanges,TransportRole,permissiongroups,MaxMessageSize
Name : Default EX2013
AuthMechanism : Tls, Integrated, BasicAuth, BasicAuthRequireTLS, ExchangeServer
RemoteIPRanges : {::-ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff, 0.0.0.0-255.255.255.255}
TransportRole : HubTransport
PermissionGroups : ExchangeUsers, ExchangeServers, ExchangeLegacyServers
MaxMessageSize : 35 MB (36,700,160 bytes)
Name : Client Proxy EX2013
AuthMechanism : Tls, Integrated, BasicAuth, BasicAuthRequireTLS, ExchangeServer
RemoteIPRanges : {::-ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff, 0.0.0.0-255.255.255.255}
TransportRole : HubTransport
PermissionGroups : ExchangeUsers, ExchangeServers
MaxMessageSize : 35 MB (36,700,160 bytes)
Name : Default Frontend EX2013
AuthMechanism : Tls, Integrated, BasicAuth, BasicAuthRequireTLS, ExchangeServer
RemoteIPRanges : {::-ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff, 0.0.0.0-255.255.255.255}
TransportRole : FrontendTransport
PermissionGroups : AnonymousUsers, ExchangeServers, ExchangeLegacyServers
MaxMessageSize : 36 MB (37,748,736 bytes)
Name : Outbound Proxy Frontend EX2013
AuthMechanism : Tls, Integrated, BasicAuth, BasicAuthRequireTLS, ExchangeServer
RemoteIPRanges : {::-ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff, 0.0.0.0-255.255.255.255}
TransportRole : FrontendTransport
PermissionGroups : AnonymousUsers, ExchangeServers
MaxMessageSize : 36 MB (37,748,736 bytes)
Name : Client Frontend EX2013
AuthMechanism : Tls, Integrated, BasicAuth, BasicAuthRequireTLS
RemoteIPRanges : {::-ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff, 0.0.0.0-255.255.255.255}
TransportRole : FrontendTransport
PermissionGroups : ExchangeUsers
MaxMessageSize : 35 MB (36,700,160 bytes)
4. Recreated the Receive connector for my photocopier/scanner but this time choose Frontend Transport role and Not the default Hubtransport. Restarted the server, crossed my fingers and everything worked!! (Apparently restarting both transport services
is sufficient, but hey I just want to be sure it works from reboot in future.
Exchange SP1 will break any custom receive connectors that you have made prior to installing the update (nor even warn you that you're about to create an addition hub transport connector on port 25 after the SP1 update, there should
be only one hubtransport on port 25 as I understand it, its ok for Frontend transport) . The transport service will not start, so to save you the hassle of deleting your custom connector just run this command from an elevated exchange powershell command to
change the custom connector from hubtransport to Frontend Transport then start the transport service. ( you may have to kill the Transport service .exe process in task manager, then start the transport services after this amendment from the services.msc panel)
Set-ReceiveConnector –Identity "Your Receive connector name" –TransportRole FrontendTransport
Alternatively, delete and re-create the receive connector and set its role to
FrontendTransport and NOT HUBTRANSPORT !!!!!!!!!!!
This issue occurs if there is a receive connector of Transport type
HubTransport that has the binding set to port 25 on the affected Exchange 2013 server. On an Exchange 2013 server that has both back-end and front-end roles, only the
FrontendTransport server-type receive connector should have the binding set to port 25.
To fix this issue, run the following cmdlet to change the connector type from
HubTransport to FrontendTransport:
Source: http://www.msexchange.org/kbase/ExchangeServerTips/ExchangeServer2013/ManagementAdministration/exchange-server-2013-sp1-transport-service-stops-and-does-not-restart.html
FIXED - Exchange 2013 - Can I Recreate Default Frontend Receive Connector SAFELY?
