DNS cache?

[bormans]

Is it possible to make a compete cache DNS from a primary?
My configuration:
- 1 DNS master server for my internal usage with myzone on Win2000 on my main site.
This DNS is the only one that can go through the firewall for rinternet resolution.
- 7 DNS Slave for myzone located on 7 different site linked by slow leased line (64k). They are also configured with forwarder adress of my master DNS.

It work well for myzone, but from a remote site, when I will surf, the first seconds, it's very slow. It seems that each time, the slave DNS ask to the master the resolution of the name.
Is't possible to make the secondary DNS exact "copy" of the master?

[U.SivaKumar_2]

Hi,

will the DNS slave do Zone Transfer from DNS master ?

what do you mean by DNS slave ?.


If you mean DNS slave as a real DNS slave doing zone transfers from DNS master then zone transfer will only replictate zones for which master server is autoritative. It wont replicate the cached data from master server.

To reduce the load on master servers and improve the DNS lookup response for WAN networks you have to configure a caching DNS server with master servers as forwarders.

So if a new query is placed the caching server will contact the master server and master server will contact the Internet DNS servers and returns the IP address to caching server which inturn answers the client . This returned address will be cached in caching server.

So next if any client query the same DNS name the caching servers will return the IP record from its memory itself. it will not contact master server again to resolve the address already cached.

regards,
U.SivaKumar

[Sergejs Svitnevs]

The Slave DNS server update its database from the Master DNS server (zone transfer) so all the zones files we configure on the Master DNS server are copied to the Slave DNS server, which acts as a backup in case the Master DNS server fails.

You should check your network configuration.

Regards,
Sergejs

[bormans]

Thanks for your explanation. It confirme what I have seen during my tests.
I will configure with forwarder.
Each time I restart my linux server, we looze the cached address.
Do you know if there is a possibility to make a dump to a file of the cached address and to load it at restart?

[Sergejs Svitnevs]

You can dump the cache (use rndc dumpdb (BIND 9) or ndc dumpdb (BIND 8)), but not reload it.

Regadrs,
Sergejs