caching-nameserver -

[Tim]

On Sun, 2007-04-29 at 13:08 -0400, Bob Goodwin - W2BOD wrote:
> another question comes to mind, my resolv.conf is as follows:
> 
> cat /etc/resolv.conf
> 
> nameserver 127.0.0.1
> nameserver 208.67.222.222               #       OPENDNS.COM
> nameserver 208.67.220.220               #       OPENDNS.COM
> nameserver 12.189.32.61                 #       Wildblue dns
> 
> I am assuming that it will go through the local cache first, then drop
> down through the servers specified sequentially until it hits?  Am I
> right in that assumption?

Your computer will try using the first DNS server in the list (first
being the topmost).  If it gets an answer, even a "there is no answer
for your query" type of answer, it won't ask anything else.  But if a
DNS server is unresponsive, after the time out period (which can be
quite long), it'll start using the next server.  And slowly walk down
the list trying each in turn.  The next query will do the same (start
from the top, and work down).  Because of that delay, you don't want a
bad entry in your list.

> This computer finds the new .com web address, but from my daughters
> Mac and the others on the Wildblue dns they still have to enter the
> address numerically.  The hosting company said it should work within
> 48 hours, worst case 72 ...  Mine worked almost immediately.   

What's this "new" address?  One recently registered?  The company is
right that some things will take a while to trickle through.  Some DNS
servers cache things longer than they should, including "no answer"
results.  And if your query goes through them in the middle, it's a
while before you get the right answers.

If you want to check sooner, you can do a dig query against the name
server actually hosting the records.  That should work straight away,
unless they're slack and not enterred the data.

e.g. dig example.com @a.iana-servers.net

-- 
(This box runs FC6, my others run FC4 & FC5, in case that's
 important to the thread.)

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