Replacing DNS server

[Kevin Darcy]

Jim wrote:

> Ok ,here is a situation. We have now two DNS servers: dot.something.com
> and dash.something.com . We want add new two servers
> dnsdot.something.com as a primary and whatever.something.com as backup
> and discontinue using thre present ones.  we have aliases for tyhe two
> existing DNS servers. The problem is some our clients domains which was
> registered with Internic have the real DNS servers as primary and some
> have the alias listed as primary  What is the "best practice" method of
> bringing the new DNS server onlne and getting rid of the old ones?
> Should we change all records pointed to the 'real'  DNS servers to alias
> records?

It's not legal to use an alias as the target of an NS record. And there is
really no distinction between "primary", "secondary" and
"backup" nameservers -- other nameservers just use whichever NS they
prefer, in the case of BIND, the preference is for faster servers over
slower ones, regardless of the order of the NS RRset they receive.

The least disruptive way to make the transition is to set up the new
servers as slaves, add them to the NS records for the zones (for a total of
4 NS'es per zone), wait for that change to propagate, change the
master/slave relationships around behind the scenes, then remove the old
NS records.You may be able to speed this process up somewhat by reducing
the TTL values on the records which are going to change (so that you don't
have to wait as long for the change to propagate), but you're still limited
by the speed at which your registrar can process the updates.


- Kevin