Performance Issues - PTR Records

Thu Nov 3 00:38:30 UTC 2011

On Wed, Nov 2, 2011 at 6:08 PM, Barry Shein <bzs at world.std.com> wrote:
> Another practical problem with this approach is that .IN is India but
> hey, at least it blocks something :-)

There are also some services out there that block connections
entirely, if the user doesn't have a PTR record.
I'm thinking IRC servers, MUDs,  and some other services with strange
security policies that check for a port 113 IDENT response and RDNS to
make a dark magic security decision to block a user who has no PTR.

But in the modern world... more commonly,  MTAs such as sendmail are
often configured to require a valid PTR record.     So as an ISP, you
may be breaking your user's local MTA if you don't have the correct
PTR for their IP addresses.

So I would say following the RFCs and implementing the proper PTRs
will help with that performance issue as a side-effect  of having a
valid zone,  and   head off   other issues  with  possibly less
popular services that are still blocking connections based on lack of
proper PTR. :)

> --
>        -Barry Shein, that'd be .ID for Indonesia

--
-JH