Two More Questions on Hosting Three Domains on One Name Server

[Ejay Hire]

Answering the reverse dns question, most mail servers look
at the following..

1.  Does reverse dns exist.  (75% of mail servers)
2.  ... If I query the A record of what's returned, does the
ip match. (50% of mail servers)
3.  ... Does the MX of the domain in the from address match
the ip?  (.1% of mail servers, usually as part of a spam
scoring solution)

So you should be fine with this reverse DNS configuration.

-ejay

> -----Original Message-----
> From: bind-users-bounce at isc.org 
> [mailto:bind-users-bounce at isc.org] On Behalf Of Tom Naves
> Sent: Thursday, February 02, 2006 2:43 PM
> To: Bind Users Group
> Subject: Two More Questions on Hosting Three Domains on
One 
> Name Server
> 
> I am going to host three domains on my dns servers:
> 
> mydomain.com
> mydomain.net
> mydomain.de
> 
> The NS Record for each domain is:
> 
>         IN        NS        nameserver1.mydomain.com.
>         IN        NS        nameserver2.mydomain.com.
> 
> Here are the SOAs for each domain:
> 
> mydomain.com.        IN        SOA
nameserver1.mydomain.com. 
> dns.mydomain.com.   (
> 
> mydomain.com.        IN        SOA
nameserver1.mydomain.com. 
> dns.mydomain.com.   (
> 
> mydomain.com.        IN        SOA
nameserver1.mydomain.com. 
> dns.mydomain.com.   (
> 
> In summary, I am using the same master and slave
nameservers 
> to host the 
> three domains.  I am using the same SOA and NS records for

> each of the three 
> domains.
> 
> Is this correct?
> 
> I have another problem with the reverse lookup zones.  All

> three domains are 
> on the same subnet and all three of the mail exchangers
are 
> on  two hosts:
> 
> mail.mydomain.com is on          192.168.40.20
> mail2.mydomain.com is on        192.168.40.21
> mail.mydomain.net is on            192.168.40.21
> mail2.mydomain.net is on          192.168.40.20
> mail.mydomain.de is on             192.168.40.20
> mail2.mydomain.de is on           192.168.40.21
> 
> It looks to me that I cannot have a reverse lookup for all

> mail exchangers. 
> So I will have reverse lookups for:
> 
> 20        IN        PTR        mail.mydomain.com
> 21        IN        PTR        mail.mydomain.net
> 
> and none for the other four mail exchangers.
> 
> Should this be o.k.?
> 
> Sorry for belaboring this, but I cannot find the
information 
> andywhere.  It 
> appears, sigh, to come with experience.
> 
> Thanks,
> 
> Tom Naves 
> 
> 
>