On Thu, 28 Jul 2005, Brad Knowles wrote:
>       Any time there's truncation, the resolvers have to retry with
> TCP.  Given broken firewalls and all the other known problems, this
> causes very serious issues with the nameservers for the project.
> This also causes problems for many NTP clients that use pool.ntp.org,
> because they can't get good (or any) DNS resolution within this
> domain.  The very low TTLs cause this problem to be compounded many
> times over.

Is support for EDNS0 ( DNS UDP packets bigger than 512 octets) common?
This should keep a significant number of the queries staying as UDP.

A quick check shows a good percentage of the queries have ( from a
tcpdump) things like:

 OPT  UDPsize=2048
 OPT  UDPsize=4096

at the end which I assume is this options turned on.

of course some people config their firewalls to block udp port 53 packets
bigger than 512 octets.


-- 
Simon J. Lyall  |  Very Busy  |  Web: http://www.darkmere.gen.nz/
"To stay awake all night adds a day to your life" - Stilgar | eMT.

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