DNS serch order

[rkmorrow]

Sorry for the post with no subject line.

We have a situation that I am wondering about as far as the search order for DNS in the TCP/IP properties on Microsoft NT 4.0

I have read that on an NT server that the second DNS server(entered in TCP/IP properties) does not get queried unless the first server is completely unavailable.

For example: if you are looking for cisco.com and you have a local DNS server in the list first, which does not have the cisco entry, the search will NOT go onto the next DNS server and try to resolve the name.

The only way the second server resolves names is if the first is down completely.

This is the way I understand it works, but I have run into a situatuation that is working contrary to this.

Can someone help me out with this, I would appreciate it.

Thanks,

rkmorrow

 

[pansophic]

rkmorrow,

DNS sends a query to the primary nameserver first. If there is a timeout condition, then the DNS application should send a request to the secondary and tertiary nameservers essentially at the same time. I believe that the default configuration is for a 4 second timeout on the primary nameserver.

If the nameserver responds, it should respond with either an IP address, or a host not found response. Either way, the secondary nameserver should not be called.

The reference to the nameserver being down was probably intended to mean that it did not respond, not that it was actually down. Under normal conditions, there shouldn't be any scenario in which it takes the nameserver more than 4 seconds to respond if it is operational.

pansophic