Name based hosts and bind

[Bob Hoffman]

So each ip will have one ptr.
http://www.bobhoffman.com/forums/viewtopic.php?t=55 is my list so far by the
way.

So if I have exmaple.com and example2.com both on the same ip, the arpa file
will have

1.123.123.123 IN PTR localhost.example.com ; example.com is the ip based one

So any site I use in that ip as a name based will use that PTR record.
So mail.example2.com will show up when aol.com checks my mail from
mail.example2.com and it will not look like it came from mail.example.com?

As a side note. I did not see anything in the books that dealt with this. If
the answer to this is above, then I guess it sort of makes sense and I guess
that is why they skipped even mentioning it...but it just seems 'odd' that
it would work to resolve ip to name without really mentioning the other
sites...

At least that means I do not have to do a reverse for each website, less
typing!!!

How would you test if your ptr is really working the way it is supposed too?


> -----Original Message-----
> From: bind-users-bounce at isc.org 
> [mailto:bind-users-bounce at isc.org] On Behalf Of Fr34k
> Sent: Wednesday, April 23, 2008 2:38 PM
> To: bind-users at isc.org
> Subject: Re: Name based hosts and bind
> 
> Hello,
> 
> Not to say that Jeff needs re-enforcing, but from experience:
> 
> We hosted thousands of web sites on one server.
> We hosted thousands of email domains on another server.
> 
> All respective servers had a single PTR, each.
> That is, only one PTR per IP address.
> 
> I hope this helps.
> 
> ----- Original Message ----
> From: Jeff Reasoner <jeff.reasoner at mail.hccanet.org>
> To: Bob Hoffman <bob at bobhoffman.com>
> Cc: bind-users at isc.org
> Sent: Wednesday, April 23, 2008 1:56:29 PM
> Subject: Re: Name based hosts and bind
> 
> Unless it's a mail server you're trying to set up the 
> existence of or even data in PTR records generally doesn't 
> matter. You don't need PTR records for Apache virtual hosts, 
> possibly just for the host itself.
> 
> Come to think of it, even if your DNS server was also mail 
> server and running httpd with namevirtualservers in it's 
> config, you'd still still only need a valid PTR for the 
> domain MX to get most of the world to accept your mail.
> 
> BTW, you do need to have the IP address block delegated to 
> you before the world will even query your server for the PTR records.
> 
> On Wed, 2008-04-23 at 13:36 -0400, Bob Hoffman wrote:
> > Hi,
> > 
> > Still having fun getting the old webserver up and running.
> > 
> > As I am dealing with getting PTR records to work perfectly for the 
> > first domain, which is also the nameserver domain, I came 
> across this 
> > little issue that is not touched upon in the Oreilly or ProDNS 
> > books.....namebasedhosts sharing the same IP address.
> > 
> > The server is both a caching and authoritive for my server and my 
> > sites on the server. But many sites will be 'name based', 
> this means 
> > sharing the same IP address.
> > 
> > Since they are sharing the same ip address I find that the 
> > in-addr.arpa file would be the same one. However, both books stress 
> > that BIND will choke during use if you have two addresses 
> listed for 
> > the same IP as in the example
> > 
> > Mysite.com IN PTR 123.123.123.4
> > Mysite2.com IN PTR 123.123.123.4
> > 
> > I would assume that both sites would end up using the same 
> addr.arpa 
> > file 123.123.123.IN-ADDR.ARPA due to having the same exact 
> ip address, nes pas?
> > 
> > I did a search online but could not find an example that 
> showed named 
> > based and ipbased on the same server/dns configuration. PTR 
> is fun-duh-mental!
> > 
> --
> Jeff Reasoner
> HCCA
> 513 728-7902 voice