How to check a Reverse DNS / PTR record on a domain

[Mark]

How to check a Reverse DNS / PTR record on a domain

1) Find the host name of their mail server
nslookup
set type=mx
company.com

Let's say in this test the result is mail.company.com

2) Ping mail.company.com and get the IP

3 Do a PTR lookup on the IP
nslookup
set type=ptr
IP ADDRESS HERE

It should resolve back to mail.company.com