Microsoft has released an excellent tool called Pelnet created by MSFT Michael Hall. This tool can be used for validating the transport changes like changing config of send connectors and everything.

This tool can also be used for troubleshooting mail flow issues i.e., connectivity issues with transport servers as well.

Basically it’s a Power-Shell script which does this transport validation as well.

Few Advantages of using Pelnet

1) IT can be used in organization where the Telnet Functionality on member servers is disabled due to security reason.

2) Manual testing of Telnet and NSLOOKUP on each and every transport servers can be eliminated which consumes more time. 

Just download the script from the Tech-net Gallery

http://gallery.technet.microsoft.com/office/PelNetps1-1cb7b6d7

Open exchange management shell and navigate to the location where we have this script downloaded

You can run update-help for the list of parameters that can be included

Refer below Microsoft Team blog for few more examples.

http://blogs.technet.com/b/exchange/archive/2014/04/30/released-introducing-pelnet.aspx

Below is the output of get-help with example

Now as a part of testing in Exchange 2010 & 2013 mixed environment I just performed the following task

Disabled the transport services on Exchange 2013.

Created a test Send connector in Exchange 2010 .

Included only address space Toybox.com on the test send connector.

Now ran the script and below is the output

It was able to identify the test send connector with the address space toybox.com.

Also it throws an error connecting to Exchange2013 since we have stopped the transport services on the Exchange 2013 servers.

Additionally it creates associated txt files in the script location as well.

This script can be used for daily monitoring the mail-flow for few parameters to check the source transport server’s functionality. It can be executed on a specified time by using the Windows Task Scheduler.