Planning for Emergencies -- A DNS Solution ?

wwebb at wwebb at
Fri Mar 17 19:20:45 UTC 2000

> Actually, I susupect he wants to know how to use BIND to implement failover
> for other servers, i.e. if the primary server fails, the DNS entry should
> be updated automatically to point to the backup server's IP address.
> Sorry, BIND doesn't have this type of functionality built-in.  Look into
> products like Cisco Distributed Director.

Does that take one of those  $50,000 Cisco 7500 series routers 
that looks like a small refrigerator ? :-)

While perhaps not as elegant, what would be the drawbacks of this 
DNS alternative:

Place the primary DNS server on the same server as 
the primary web server and the secondary DNS server  on the 
same server as the secondary web server.  The primary DNS 
server has an IP pointing to the primary web server. The secondary 
dns server has an IP pointing it to the secondary  web server.  Both 
dns records have very short TTL's.  

If the primary goes down, then the primary dns server 
fails as well and people would automatically be routed to the 
secondary dns server, which would push them to the working 
website on the secondary network..  The secondary server would 
also que mail for the primary, until it came online. 

Also if the both networks are up, and the primary's pipe becomes 
congested, then the site would be served up by the secondary...

I suspect this solution will not be found in any RFC ;-)

Bill Webb 

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