Exchange server 2010 can send mail but no receive anything.

Current setup :

 

PTR --> x.x.x.1 (internal ip) point to 1.2.3.4 (public ip)
domain controller = x.x.x.1 ( abc.com )
exchange server = x.x.x.2 (internal ip)

iv setup the the PTR in the DNS server on the domain controller.
Have also setup the forwards in DNS Server on the domain controller.

For some reason the mx record keeps showing the local ip ( x.x.x.2 ) on mxtoolbox.com

Any idea why it keeps showing the internal IP of the exchange server?