domain name length vs character string length

Jack Tavares j.tavares at
Wed Oct 18 07:36:51 UTC 2006

A question:
the library routine
limits a domain name to 255 characters (per RFC1035)
So, running named-checkzone (or named) with a RR with a domainname
longer than 255 gives an "out of space" error. (bind9.3.2)
arpa/nameser.h lists
#define NS_MAXDNAME 1025
#define NS_MAXCNAME 255
and NS_MAXDNAME is used in many places in the bind code to expand
dns names received over the wire.
So, does this mean one can have a domainname in wire format that,
converted to string representation) can be greater than 255?
If so, one could not put that in a zone file, because named complains
about it on start up.
Thank you

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