Exchange 2010 Legacy Relay needs to increase maximum connections per source

Move Exchange 2010 Legacy Relay (PowerPMTA) from Exchange 2003  connector server to Exchange 2010 Hub

 

you will see connections per source exceed the limit error. By default, Exchange 2010 Hub only offer 20 connection per source IP.

 

Solution:

 

Create a dedicated receiving connector for PMTA. from Exchange 2010 Powershell

 

get-receiveconnector -id "hubServername\From PMTA" |FL

 

to see what parameters need to be modified to meet your needs, then run

set-receiveconnector -id "hubServername\From PMTA"  -MaxInboundConnectionPerSource 500 -MaxInboundConnectionPercentagePersource 10

 

Note: by default, MaxInboundConnection per server is set 5000, thus 500/5000 =10%