Wireshark-dev: Re: [Wireshark-dev] ADNS alternative
From: Jaap Keuter <jaap.keuter@xxxxxxxxx>
Date: Sun, 04 May 2008 07:25:06 +0200
Hi,

Quoting UDNS:
"Most applications that requires asyncronous DNS processing either implements their own resolver modules (which, again, is not a trivial task, and sometimes leads to incompatibilities with other resolver libraries and bugs which are difficult to find), or uses forked-resolver model, where separate process is forked just to perform DNS queries, which requires quite some resources, especially when an application already have some sort of event loop in place to multiplex I/O. Asyncronous DNS resolver is a must for many nowadays applications, such as GUI (GUI-application should not stop processing user interface events while performing DNS queries), high-performance servers (such as mail servers) using event-loop model (see for example an excellent "The C10K problem" page at kegel.com describing various methods to handle many client requests in parallel)."

So you are forewarned it is not a trivial task. :( Then again what do we need? Reading documentation on most libs reveals that the problems start with the other stuff, not so much with A_NAME and AAAA_NAME records. But then again, when that part is not too hard, why not use an available library for that that is at least good at that?

Thanx,
Jaap


Stephen Fisher wrote:
All very interesting alternatives to adns. I found a few others searching the Internet. Why is everyone starting but not maintaining an async dns library? :) I don't like adns because it isn't maintained very much, but I'm afraid of trying something else and it being less stable.

Maybe this is something we should build into Wireshark since it is such an important feature? Lots of work I'm sure. What made me think of this was running across old web pages talking about Netscape and its built-in(?) async dns resolver ;).


Steve