On Tue, 14 Mar 2000, Pete Templin wrote:

On Tue, 14 Mar 2000, Marc Slemko wrote:

...

Saying "the clients's primary DNS" is misleading. There is no way to know what the "primary" DNS server is for a zone, and there may not even be what is typically known as a primary.

What if it's a UUNet resold modem to a client of iAmerica - what server gets used then? We know that UUNet's DNS servers are likely to not be located close (in net terms) to the client, and how do we know what DNS servers are being assigned to the client?

User's machine contacts caching nameserver x to do a lookup. Nameserver x contacts authoritative nameserver y, which then works out where x is before returning an RR that's good for wherever x is. If n isn't net.near to the user's machine, then something's a bit weird. If part of a dialup ISP's internal network falls over, you hardly want every single user's resolvers to fail!

Or what if my clients get assigned dns servers in 192.168.254/24? Sounds to me like it's not a valid geographic identifier.

I'd hope that nameserver would talk to the world with a real source address, which y would then use to do a proximity test, rather than a 1918 address - at least it should if it actually wants to get a response. What address the client-side interface uses is neither here nor there. -- Patrick Evans - Sysadmin, bran addict and couch potato pre at pre dot org www.pre.org/pre