SUMMARY:Limit on nameserver entries in resolv.conf for DNS

From: Cathy Smith (
Date: Wed Nov 12 1997 - 10:19:19 CST


thanks to everyone who replied. my original question

> can someone tell me what the consequences are of
> including more than 3 nameserver entries in the
> resolv.conf file. the os is 4.1.4, and the
> version of bind shipped with that os.
> my supervisor says that limiting the number to
> 3 is a recommendation only.

the limit is set in /usr/include/resolv.h with the
variable MAXNS. the default value for Sun OS 4.1.4
is 3. this is also given in the man page on resolv.conf.
i checked and no one here has rebuilt and
installed newer versions of bind.

the general consus was that additional nameserver
entries are ignored. evi smith's book,
_UNIX System Administration Handbook_, states that
Bind begins with the first name server listed in the
resolv.conf file, and queries each server 4 times
before going to the next entry.

several people reminded me that the version of Bind
shipped with 4.1.4 is old, outdated, and buggy. i
will look into building and installing the latest version
after i get this DNS subdomain set up and running.

the current maintainer of Bind is the Internet Software
Consortium at they have links to a lot of
useful things there.

again thanks to the following people who replied:

Gary Smith <>
John Fusselman <
Joel Lee <>
Rick Kelly <>
Glenn Satchell <>
James Ashton <>
Rich Kulawiec <>
Stephen Frost <>
Christopher L. Barnard <>
Rodney C. Marable <>
Arthur Hyun <>
David Dhunjishaw <>


Cathy L. Smith
Dallas Semiconductor

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