RE: [cobalt-users] Shared IP Address: DNS / Website - Good / Bad Practice?

["Rodolfo J. Paiz \(E-mail\)" <rpaiz@xxxxxxxxxxxxxx>]

> The company we lease the RaQ3 from said that we could run a 
> website on the base IP address along with DNS service.

Right.

> This would basically save using one of the 16 additional IPs. 
> To do so, we were told to name the RaQ3 host as "WWW".  So it
> appears as www.ourcompanyname.com.  We registered the DNS
> server name with Network Solutions as www.ourcompanyname.com. 
> Registration was successful.  We published a website to the base
> IP address.  DNS and the website work fine.

Right.

> Ordinarily DNS servers are named something other than "WWW" 
> like "NS1", etc. This would seem to preclude sharing the same
> IP with a website.

Oops, wrong. A single computer can answer to several different
names and there's nothing wrong with that. Heck, my little Sun
at home answers to ns2, www, ftp, smtp, pop, imap, secure, gw,
and sun.

A single computer can also run multiple *services* and there's
nothing wrong with that. You simply know that if the computer
goes down, they all go down. But your ISP is taking a simple
approach: you could also have told your RaQ to answer to both
ns1 *and* www on the same IP, and no one would care. The good
thing about using different names is, it's very easy to migrate
later if your load gets heavier. I always use smtp.* and pop.*
hostnames in my client configurations, even though they always
point to the same machine. But if ever I should want to make
them separate, this way takes 10 seconds of work (point smtp.*
to a new IP address) while if they all use mail.* for in and
out then I'm stuck keeping SMTP and POP traffic on a single
server.

> Is sharing a base IP address between a DNS and website good
> or bad practice??  It seems to work but are there potential
> problems that we were not made aware of?

It's totally irrelevant. DNS service and web service simply
have nothing to do with each other. The only thing is, you do
need to have two DNS servers on two different IP's (ideally
on two different networks) so that one of them is always up
even if your entire company goes south temporarily. Primary
and secondary DNS *should not* be on a single machine.

You can do it, but it's not a good idea. If your single
computer with www and ns1 goes down, the other computer with
ns2 (maybe at your ISP's location) will tell the world you're
unavailable. But if ns1 and ns2 both die, the clients will be
told the domain or host does not exist. In the eye of the
sysadmin, it's the same thing: they didn't get a webpage.
But in the eyes of the customer... they're very different.

-- 
Rodolfo J. Paiz
rpaiz@xxxxxxxxxxxxxx <mailto:rpaiz@xxxxxxxxxxxxxx>