Location: United States [City: Los Angeles, California]

Preparation:
The  reverse DNS entry for an IP is found by reversing the IP, adding it to "in-addr.arpa", and looking up the PTR record.
So, the reverse DNS entry for 209.85.22.2 is found by looking up the PTR record for
2.22.85.209.in-addr.arpa.
All DNS requests start by asking the root servers, and they let us know what to do next.
See How Reverse DNS Lookups Work for more information.

How I am searching:
Asking f.root-servers.net for 2.22.85.209.in-addr.arpa PTR record:  
       f.root-servers.net says to go to basil.arin.net. (zone: 209.in-addr.arpa.)
Asking basil.arin.net. for 2.22.85.209.in-addr.arpa PTR record:  
       basil.arin.net [192.55.83.32] says to go to ns2.ev1servers.net. (zone: 22.85.209.in-addr.arpa.)
Asking ns2.ev1servers.net. for 2.22.85.209.in-addr.arpa PTR record:  Reports that no PTR records exist [from 207.218.247.135].

Answer:
No PTR records exist for 209.85.22.2. [Neg TTL=7200 seconds]

Details:
ns2.ev1servers.net. (an authoritative nameserver for 22.85.209.in-addr.arpa., which is in charge of the reverse DNS for 209.85.22.2)
says that there are no PTR records for 209.85.22.2.

To get reverse DNS set up for 209.85.22.2, you need to speak to your Internet provider.  You could also
check with admin@ev1servers.net., who is in charge of the 22.85.209.in-addr.arpa. zone.

Note that all Internet accessible hosts are expected to have a reverse DNS entry (per RFC1912 2.1),
and many mailservers (such as AOL) will likely block E-mail from mailservers with no reverse DNS entry.
To see the reverse DNS traversal, to make sure that all DNS servers are reporting the correct results, you can Click Here.