One IP Address and multiple domain names

[Kevin Darcy]

Barry Margolin wrote:

> In article <9sursr$dho at pub3.rc.vix.com>, HS <herve.schlecht at wanadoo.fr> wrote:
> >In the reverse zone can I declare the same address with two different domain
> >name :
> >ip_address1    IN    PTR    www.domain1.com
> >ip_address1    IN    PTR    www.domain2.com
>
> You can, but you don't have to, and I don't recommend it.  Just pick one (I
> suggest using the one that matches the name that the machine uses for
> itself).
>
> >If I take this information in my reverse zone that are the response I
> >receive if I take an reverse resolution for the ip-address1 ?
>
> Reverse resolution will return both names.  If the application is just
> doing reverse resolution so that it can display a name to the user it will
> probably use the first one it gets, and if the nameserver performs
> round-robin it could be a different one each time.  That's why I don't
> recommend having multiple PTR records -- it causes non-deterministic
> behavior.

The BIND code has a special case for PTR records and won't round-robin them by
default.

But who knows what other nameserver implementations may do?


- Kevin