DNS Question

[ROSS HANSON]

Can you have two primary DNS servers instead of a primary and
a secondary??

Thank You

[Kellogg Unix Team]

Technically, yes. But that would imply that you now need to keep them in sync. Any change in one's data need to be reflected in other's. Of course, I am assuming that you are talking about the same zone. If you set the other one as secondary, the zone data are transferred.

Are you thinking of setting up split-DNS?
:-)

...Manjeet

[Byron Myers]

Yes, The this is the design of the Internet. But as stated earlier, this is best suited for differing zones. Otherwise, you will have to manage synchronizing the two servers.

[ROSS HANSON]

These are not differing zones,
if I get your meaning. These both will have the same information on them. But if one
goes down you can automatically
switch to the other

[Kellogg Unix Team]

OK, I got it. This is one of the ways to provide redundancy. In client's /etc/resolv.conf (and equivalent PC file), you can enter IP addresses of both servers. In case one goes down, you will be served by second server, albit with a little delay.

...Manjeet

[John Bolene]

syncronizing the servers is very easy, just set one up as secondary to the primary and have it pull its data from the primary

with lines such as

secondary mydomain.com server.ip.from.here dirs-to-copy

I have 2 root servers for my small internal domain which also forward internet lookups outside.

Setting up your resolv.conf with the primary then the secondary is easy. There is a delay in 10.20 if the primary cannot be found, but this is configurable in 11.

[Christopher Caldwell]

From the client's perspective, there is little difference between primary and secondary servers. All authoritative name servers appear in the SOA record - you don't say one is primary and one is secondary.

From the server standpoint, secondaries "pull" zones from primaries - or in more modern versions of bind, primaries can push zones to secondaries.

It's certainly possible to configure all primaries (no secondaries) by hand building the zones on all of the relevent servers. You'll then have to devise a mechansim to keep the zones sychronized (in the case of the primary/secondary, synchronization is handled for you).

[ROSS HANSON]

Ok I admit I am slow!
How do you get the primary to
"push" to the secondary??

[U.SivaKumar_2]

Hi,

yes , you can have two primary DNS servers with same data.

COnfigure DNS in two servers manually putting every entry for the same zone.

register these servers as DNS servers for your domain in the Internet.

This would work for static DNS environments ( No changes in DNS records ) .

But in Large (changing) DNS environments if you add a new record to one of the DNS server then you will have to add the same to the second server also manually.

regards,
U.SivaKumar

[Steven E. Protter]

You can use cron to synch them up. It means using NFS or CIFS or rcp or scp, to copy files from one server to the other.

cron can then stop/start the deamon on the target server.

I use this methodology on a NSP web hosting setup I run personally on Linux.

For real realiability though, I should have the second DNS server at a different physical location.

Steve