How many nameservers?

bsfinkel at bsfinkel at
Mon Feb 2 20:25:35 UTC 2009

On Sun, Feb 1, 2009 at 7:51 PM, shulkae <shulkae at> wrote:

>> How may NS entries typically is allowed per zone? Is there a bind
>> limit or does it cause any side effects if the
>> slaves are geographically distributed ?
>> We would like to setup one zone for my new group who have offices all
>> over the world ? We are planning
>> to use BIND 9 over FreeBSD. There may be few SUN/Solaris hosts as
>> well.
>> We would like to start with around 16 Slaves per master per zone. Is
>> this too much? My tests did not reveal any side effect fortunately.
>> Anyone with experience of setting up DNS slaves all around the globe
>> please advise..

and Ben Croswell <ben.croswell at> replied:

>I have never heard of there being any downside to a large number of NS
>records for a domain.
>I know internally to my company we have large numbers of NS records for the
>internal domains.

One downside - if you have many NS records, then they might not all
fit in one UDP packet (the Authority and/or Addition sections of a
response to a DNS query).  This will cause the protocol to revert
to TCP.
Barry S. Finkel
Computing and Information Systems Division
Argonne National Laboratory          Phone:    +1 (630) 252-7277
9700 South Cass Avenue               Facsimile:+1 (630) 252-4601
Building 222, Room D209              Internet: BSFinkel at
Argonne, IL   60439-4828             IBMMAIL:  I1004994

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