DNS Connection Question

[trlists at clayst.com (trlists at clayst.com)]

On 20 Oct 2004 dsr at tao.merseine.nu wrote:

> Nameservers always try 53 UDP first, because most requests and
> responses will fit into a single packet.

That implies that sometimes they don't, which makes me wonder if a 
nameserver which only accepts UDP on port 53 is fully functional.  Is 
it?  Guess I should read some more details on DNS.

> You could go to the trouble of constructing your own code, but
> why not call "dig" and see if you can get a valid response?

You know, I have to admit this partly reflects my experience outside 
the Unix / Linux world.  That makes perfect sense but I am just not 
used to starting up a separate process to answer a simple question, 
because it's not the norm in Windows or elsewhere that I've worked, so 
I don't tend to think of it.

Also I don't really want to do a full DNS query, I just want to 
establish that the named system gives the general appearance of being a 
valid nameserver.  Since I'm validating user input, timing has some 
importance and I have the idea -- admittedly not tested, but logical -- 
that just opening and closing a connection is likely to be a lot faster 
than doing the full query.

--
Tom