The following powershell command can be executed to create a new Exchange 2010/3/6 SendConnector to send all outbound email via the 'smarthosts' associated with your mailRelay service:
New-SendConnector -Name "YorkUK Hosting Smarthosts" -Usage Custom -AddressSpace "SMTP:*;1" -DNSRoutingEnabled $false -SmartHosts "relay1.uksmtp.co.uk","relay2.uksmtp.co.uk" -MaxMessageSize 50MB -port 587 -ForceHELO $False
Please note that if you have any existing SendConnectors configured you may need to remove or re-configure them to ensure the newly created connector sends outbound email via our smarthosts.
Troubleshooting
Ports
If your firewall or Internet provider blocks port 25 it is possible to use the smarthost service using TCP 2525 or 587. To use the alternative port you will need to update the send connetor to use the new port. From a PowerShell prompt, enter the following:
set-sendconnector -identity "YorkUK Hosting Smarthosts" -port 2525
Following the update you will need to restart the Transport service:
net stop MSExchangeTransport
net start MSExchangeTransport
Disable Legacy SMTP
If your send connector is using the 'Force HELO' directive it will prevent the use of TLS to encrypt communications and potentially prohibit access to the mailRelay service. To ensure the ESMTP standards are used, disable the legacy protocol usage:
set-sendconnector -identity "YorkUK Hosting Smarthosts" -ForceHELO $False
Following the update you will need to restart the Transport service:
net stop MSExchangeTransport
net start MSExchangeTransport
Further Reading
For more information relating to Exchange 2010 SendConnector configuration please visit http://technet.microsoft.com/en-us/library/bb629503(v=exchg.141).aspx