[NTLUG:Discuss] "Back up dns server"?

[Carl Haddick]

On Tue, Dec 04, 2007 at 07:49:53PM +0000, m m wrote:
> All:
>  
> We all know that we need to have two DNS server for a domain.Usually, these two DNS server have the same A records for a domain.All of this settings are preventing the web site (mail...) failure.  
>  
> Based on the concept above, I think we should be able to set the 2nd DNS server to a different IP with same domain name as primary DNS server.
> In this case, there is a need to run 2 servers with same domain but different IP. 

Not a problem, one dns server at 1.2.3.4 and another at 4.5.6.7, both
named dns.mydomain.com - but also not giving any redundancy.

> Why is doing this?  When one of the IP is not available, another one will be still available.
>  
> Please note, this is not a web farm issue. I think this will be to fix IP (or firewall) "broken" issue.  
> 

Firewall issues?  Can you amplify on that?  Seems like that would
different from DNS, unless there is NAT or something that you need to
play tricks with.

An interesting point is the DNS servers referenced by name in whois
actually have no firm tie to the name servers that actually serve your
domain.  Whois and DNS are not connected.  Whois does not need to have
valid name servers listed for your DNS to work without trouble - but you
certainly should try to keep whois current for your domain.

To find xyz.com, a DNS client will first ask one of the root servers,
taken for granted from the client's 'hints' file, for who has authority
for '.com'.  Then the client will ask one of those servers who has
authority for 'xyz.com'.  Then, the client will ask one of those servers
for the 'A' record (or whatever you are looking for).  The process will
continue if the authority is further delegated.

Anyway, thought I would offer that - corrections welcome.  Did I get
that process right?

Regards,

Carl
 
> Am I right? Any company doing such a "back up DNS server"?
>  
> Thanks.
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-- 

=================================================================
Carl Haddick
sysmail at glade.net
PO Box 1586
Mexia, TX 76667                 Remember, Murphy was an optimist.
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