RE: How common is lack of DNS server diversity?

Regarding "search", I was simply referring to the commonly used dns
terminology referring to the "search list". See /etc/resolv.conf on any
unix system or "DNS and Bind V3", page 102. Wait a minute, I see where
your usage may have originated. W95 network config refers to the
nameserver list as "DNS Server Search Order", and to the domain list as the
"Domain Suffix Search Order". MS doesn't use this wording in W2k.

As far as specifying multiple nameservers (the "nameserver" directive in
resolv.conf, or "DNS server addresses" in Win2k), as I said before I tested
it and it worked fine in Win2k.

Test procedure:

Under "Advanced TCP/IP Settings", DNS tab, remove all nameserver addresses,
add the address of a non-existent machine, add the address of a working
nameserver. Reboot (if you're not doing this with Netswitcher). Test.
All services work fine.

Nslookup gives you an idea about what is happening under the covers:
C:\>nslookup trall2
DNS request timed out.
    timeout was 2 seconds.
*** Can't find server name for address 9.1.25.192: Timed out <- the
non-existent nameserver
Server: hawk.almaden.ibm.com
Address: 9.1.8.254 <- the working nameserver

Name: trall2.almaden.ibm.com
Address: 9.1.77.83

Nslookup will retry the nameserver list each time, resulting in a
resolution delay. But the IP stack resolver remembers which server is
working and doesn't retry the bad ones unless needed - there is no
resolution delay.

Feel free to test this on any other operating system and report your
results.

Tony Rall

Roeland Meyer <rmeyer@mhsc.com> on 2001-01-27 11:10:34