Re: Understanding DNS, Create an "Failover"

[Laurent Bigonville <bigon@debian.org>]

basti wrote:
> Hello,

Hello,

> last weekend my primary DNS-Server goes down, and some of my server
> can't find each other.
> 
> I have a Primary and a Secondary DNS-Server using bind9.
> The resolv.conf file looks like:
> 
> nameserver <MyPrimaryDNS>
> nameserver <OneOfMyISP>
> nameserver <2'ndOfISP>
> 
> For understanding:
> Is the secondary DNS just a backup of the Master for "loadBalancing"?
> What does the secondary DNS do if master is down?
> 
> How can I fix this?
> 

According to the resolv.conf(5) manpage the nameservers are used in the
specified order. The extra nameservers are used as backup if the
previous one is not answering. There is no load balancing done here.

"The algorithm used is to try a name server, and if the query times
out, try the next, until out of name servers, then repeat trying all
the name servers until a maximum number of retries are made."

Cheers,

Laurent Bigonville