DNS problems to RoadRunner - tcp vs udp

Seth Mattinen sethm at rollernet.us
Fri Jun 13 13:24:27 CDT 2008


Jon Kibler wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
> 
> Mark Price wrote:
> <SNIP>
>> >From what I have read, public DNS servers should support both UDP and
>> TCP queries.  TCP queries are often used when a UDP query fails, or if
>> the answer is over a certain length.
>>
> 
> UDP is used for queries.
> 
> TCP is used for zone transfers.
> 
> If my server responded to TCP queries from anyone other than a secondary
> server, I would be VERY concerned.
> 

I see long TXT records from some DNSBLs that won't fit in a UDP packet 
on a daily basis. Certainly nothing to be concerned about.

~Seth




More information about the NANOG mailing list