Performance Issues - PTR Records

Wed Nov 2 22:12:21 UTC 2011

From: Matt Chung [mailto:itsmemattchung at gmail.com] 
> 

> Historically, there was no compelling reason to create PTR 
> records for our CPE however more and more applications seem
> to be dependent on it.  Although we will be assigning a
> record for each address, my question is why
> is the application (specifically HTTP) dependent on a reverse record ?
> What is the purpose?
> 

As a web host, we frequently find customers who have
added Apache rules to their ecommerce sites to block
undesirable traffic, such as credit card scammers, etc.
Not knowing any better, they often do this by just
blocking anything that ends in .in to block Indonesia
for example.  Well, once you choose to block by 
resolved name, now that site has to do a dns lookup
for every incoming request to see if it resolves to a
name that should be blocked.

Just one example, but I'm sure there are countless
others that also impede performance for IP addresses
without a PTR record.

David