Secondary DNS Servers

David Botham dns at
Wed Jan 15 17:40:26 UTC 2003

> -----Original Message-----
> From: bind-users-bounce at [mailto:bind-users-bounce at] On
> Behalf Of lumux
> Sent: Wednesday, January 15, 2003 6:31 AM
> To: comp-protocols-dns-bind at
> Subject: Secondary DNS Servers
> Hi All,
> Could anyone please answer the following for me:
> If a DNS server requests the record for a domain, but the primary
> is
> unavailable and the record is retrieved from the secondary DNS server,
> log will the DNS server continue using secondary server over the

It is important to remember that Primary and Secondary (now Master /
Slave) do not carry any priority.  Therefore, a name server may in fact
decide to use the slave server for a zone if it responds faster than the

BIND uses an algorithm to pick to best name server to use for the
resolution of a particular domain name.  (someone else will pipe in with
the particulars I am sure, or, you can search the archives as I know it
has been described before here on the list)  BIND basically queries all
the listed name servers.  The one that responds first wins.  If that
name server suddenly stops responding the process is started again until
another name server wins.  I do not recall the conditions under which
the faulty name server will begin to be used again after it comes back
on line...


> Any Help would be gratefully received
> Thank You
> Lumux

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