Unexpected First Lookup Delay

[David Nolan]

I encountered a similar problem recently after upgrading bind at a customer 
site.  Extensive analysis led to a conclusion that a firewall upstream of 
the DNS server was filtering UDP DNS replies larger then 512 Bytes. 
Current Bind servers enable ENDS0 (large UDP DNS replies) by default.  But 
after the first couple queries fail eventually Bind retires without EDNS0 
enabled.  Try adding this to your config:

edns-udp-size 512;

-David

--On Thursday, September 21, 2006 12:46:52 -0500 Blair Copeland 
<copeland at unt.edu> wrote:

> I am running Debina 2.6 servers with Bind 9 code and I get an
> intermittent delay of up to 4.5 seconds the first time a given lookup
> occurs.
>
>
> Debian 2.6 Server:
>       Linux ns.unt.edu 2.6.8-2-386 #1 Tue Aug 16 12:46:35 UTC 2005 i686
> GNU/Linux
>
> Bind 9:
>       BIND 9.3.2
>
> Library:
>       lrwxrwxrwx  1 root root      16 May  7 22:09 /usr/lib/libdns.so.16
> -> libdns.so.16.0.0       -r-xr-xr-x  1 root sys  1038664 May  7 22:42
> /usr/lib/libdns.so.16.0.0
>
>
>
>
> I believe have tried the same code on Debian 2.4 without issue, however
> right now I am using 9.3.0rc2.
>
> Debian 2.6 Server:
>       Linux ns0001.public.unt.edu 2.4.26-1-386 #1 Thu Jul 22 12:46:23 JST
> 2004 i686 GNU/Linux
>
> Bind 9:
>       BIND 9.3.0rc2
>
> Library:
>       lrwxrwxrwx  1 root root      25 Jan 18  2005 /usr/lib/libdns.so.11
> -> /usr/lib/libdns.so.11.1.3       -r-xr-xr-x  1 root sys  1246960 Apr  7
> 14:25 /usr/lib/libdns.so.11.1.3
>
>
> Is anyone else running a similar configuration or have a reason not to
> run 2.6?
>
>
> Blair Copeland                                        Ph# (940) 565-4180
> Communications Manager                                FAX (940) 565-4060
> Network Operations and Services	                      TTY (800) RELAY TX
> Data Communications
> noc.unt.edu/~copeland Computing and Information Technology Center
> copeland at unt.edu
>
>