USNS issue

[Michael Tokarev]

Abhijit Pandey wrote:
> Hi Michael,
> 
> Thanks for your mail. Couple more question.
> I don't have a DNS server running locally.
> 
> Is UDNS not maintaing the resolver cache on my PC?

There's no "resolver cache" on "your PC" unless
you're running some sort of caching DNS server.

> Does your UDNS also depends on BIND-Utils ?

No.

> 1) Here is the output when I rerun the Query.  
>           I see the additional section and Answer section getting flipped.

Aha.  I see.
Damn.  Your email is garbled quite seriously, all this http:// cruft...

> [apandey at localhost udns-0.0.9]$ ./dnsget -vv www.yahoo.com

> ;; received 58 bytes response from 192.168.15.1 port 53
> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 30366, size: 58
> ;; flags: qr rd; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
> 
> ;; QUERY SECTION (1):
> ;www.yahoo.com IN A
> 
> ;; ANSWER section (1):
> ;EDNS0 OPT record (UDPsize: 4096): 0 bytes
> 
> ;; ADDITIONAL section (1):
> www.yahoo.com 10000 IN A 209.131.36.158
> 
> dnsget: unable to lookup A record for www.yahoo.com: valid domain but no data of requested type

Lovely.  So whatever is running at 192.168.15.1, it looks like it
does not understand or implement EDNSO properly, AND actually
garbles the result, because there's no CNAME record shown as below.
What it is, anyway - I mean, which DNS server is running there?

> Here is the output query when I provide the same arguments 3 times in
> the command line with -vv mode.
> 
[]
> ;; received 96 bytes response from 192.168.15.1 port 53
> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 40089, size: 96
> ;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1
> 
> ;; QUERY SECTION (1):
> ;www.yahoo.com <http://www.yahoo.com>. IN A
> 
> ;; ANSWER section (2):
> www.yahoo.com <http://www.yahoo.com>. 110 IN CNAME
> www.yahoo-ht3.akadns.net <http://www.yahoo-ht3.akadns.net>.
> www.yahoo-ht3.akadns.net <http://www.yahoo-ht3.akadns.net>. 53 IN A
> 209.131.36.158
> 
> ;; ADDITIONAL section (1):
> ;EDNS0 OPT record (UDPsize: 4000): 0 bytes

And this one looks correctly.

Try this:

 $ RES_OPTIONS="udpbuf=512" ./dnsget ...

(i.e, set variable RES_OPTIONS to value "udpbuf=512" before
running the test).  It should fix the problem.  But in any
way, the proper solution is to fix your resolver running
at 192.168.15.1.

/mjt