primary and secondary DNS on the same machine

[Simon Waters]

Dave wrote:
> 
> Hence,
> if my name server was to go down there would be no need for a secondry
> name server as the web server would be down as well. Now for my
> question...

Stop ... Think ...

This assumes that all the names in a domain refer to your
server which might happen for some domains, but won't be the
case for all of them.

The first one to go is usually mail - the client will want
mail routed to their mail servers, and maybe even a mail
relay, so when your server goes down, their email stops even
though all their servers and links are working 100%. Clients
loses big sale, client sues....

> If I have two IP addresses pointing at the same machine is it possible
> to use the same machine for a primary and secondry name server for all
> the domains I will host? Is it reccomended to do this?

Possible, but not recommended. It would just be a primary -
that it has 2 IP addresses is enough to "fool" the
registrar, who have tried to prevent you doing this by
insisting on 2 IP addresses.

> The other alternative is to use the company that is providing the co-
> location's name server for a secondary server

The colocation partner DNS is a good start, but the chances
are their DNS server is at the same physical location as
your server (almost by definition), so if you lose the site
(It happens - look at Houstons recent floods), then all the
DNS servers for that domain may be lost. If the colocation
partner has a number of sites they may offer multiple DNS
servers.

Various companies offer to act as a DNS secondary, some with
"brand names" in the DNS business, some for free.