RRSet size limitation lower than predicted by RDLENGTH field size
Mark Andrews
Mark_Andrews at isc.org
Fri Apr 25 06:37:09 UTC 2008
> We're pushing the limits of RRSet sizes for A records in the responses to
> queries for our lists, but we're finding that the practical limit is much
> lower than that predicted in the binary message format specs.
>
> The octets in the RDLENGTH param (16 bit unsigned = 65535) should allow
> 16384 A records in a single RRSET using TCP, but the behavior we are
> observing in BIND is a limitation of 4096 A records.
>
> We're using Bind 9.4.1-P1 on Gentoo.
>
> Any ideas what's causing this, or how to fix it?
Each A record takes 16 octets.
2 for the name
2 for the type
2 for the class
4 for the ttl
2 for the rdlen
4 for the rdata
65535/16 = 4095
Mark
> Thanks in advance.
>
> Tom Byrnes
> CTO
> ThreatSTOP
>
>
--
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742 INTERNET: Mark_Andrews at isc.org
More information about the bind-users
mailing list