Re: [cobalt-users] Name based hosting - Raq4

[Jeff Lasman <jblists@xxxxxxxxxxxxx>]

Ryan Denny wrote:

> About Reverse Lookup for name-based sites... should it be turned on for
> *any* site, including the home (server) site, if I plan on sharing that
> main site's IP for the other virtual sites?

<sigh>... I know the archives are full of my explanations on reverse
DNS.

DNS likes one "ptr" record (reverse DNS) for each IP#.  But most of the
time you don't do anything except tell your colocation provider; for
most of us our colocation providers handle reverse DNS themselves; they
usually do NOT delegate reverse DNS to us unless we've got a whole
C-block or more of address space.

If your upstream/colo has NOT delegated reverse DNS to you it doesn't
matter how many of these records you put on your RaQ; all you're doing
is wasting space.

However if you DO have reverse DNS delegated to you, then you really
need to do it right, which is to have ONE ptr record per IP#.

In the good old days, back when you could only have one IP# per system
and only one domain per IP#, this was easy; the ptr record pointed to
the machine-name.  So if you had a machine named "joe" at
"yourdomain.com", the ptr would be to "joe.yourdomain.com" no questions
asked.

Today, we can do that to some extent.

For example, if I've got three shared IP#s on a machine named "joe", I
can have all three ptr records pointing to "joe.domain.com".  But, if
I've got a non-shared IP pointing to an important service, i.e., a
secure site, then I may want the ptr record pointing to
"secure.domain.com".

> Because right now, my second
> site's domain name is resolving to the first (home) site's domain, which
> has the same IP.

Probably because of an error in the /etc/httpd/conf/httpd.conf file.  If
you still haven't fixed this, send us a copy of each of the virtual
hosting blocks (one for each of the two domains) from that file, and let
us know which one appeared first in the file.

Or, just delete and rebuild the problem site, which should fix the
problem.

> ( REL : Is there a way to add this Reverse Address Record to the DNS from
> the Linux console? I assume so... )

Yes, but if you do it according to the DNS books, it'll get erased the
next time you do anything DNS from the gui.  You'll need to understand
how /etc/named/records works, and that's a bit beyond the scope of this
reply.

Jeff
-- 
Jeff Lasman <jblists@xxxxxxxxxxxxx>
nobaloney.net
P. O. Box 52672, Riverside, CA  92517
voice: (909) 787-8589  *  fax: (909) 782-0205