Hello and welcome to the Tuesday, July 7th,

2006 edition of the Sands International Storm Center's Stormcast.

My name is Johannes Ulrich, recording today from Jacksonville, Florida.

And this episode is brought you by the Sandsdot edu credit certificate program in cyber security engineering.

Today I wrote a quick diary about, well, a less well-known DNS records.

I noticed recently in my home network that there were a couple of lookups for any PDR records.

And while this was a record I wasn't really familiar with,

it has been around, it has been defined for a while since around 2000.

That's when the RFC was released.

And the record itself looked, well, interesting and somewhat dangerous

in that it allows you to rewrite results using regular expressions. And we all know

regular expressions, lots of sort of implementation issues around that. Well, it turns out,

wasn't that attack, it was normal traffic. Apparently, it's used as part of the rich

communication services or RCS standard.

RCS has been introduced in recent years, and particularly the last couple of years, been deployed more and more with iOS and Google and Android replacing SMS more and more with RCS.

And these NAPDR records are used as part of SIP.

That's the underlying, well, protocol that's being used for RCS.

So RCS is essentially a more modern version of SMS.

It gets rid of some of sort of the old really sort of voice network-based craft that sort of stuck around with SMS and makes it more a standard internet protocol for IP using SIP as one of its sort of transport mechanisms here for the messages.

The NAPDR records are here used without actually taking advantage of the regal expressions.

They're really just used to communicate essentially where to connect to. I've seen them for Verizon and AT&T in my network,

but of course know what exact records you'll see

...