Reverse DNS question

laughingbuddha · Tue Jan 20, 2009 2:31 pm

Hi,

I have 2 name servers on my server, taking up the first 2 ips, but currently I have only 1 rdns setup on the first ip, and that is for server1.mycompany.net and not for the name server assigned that same ip being, ns1.mycompany.net. I also have a PTR record setup in the primary domain dns settings on that first ip which is mycompany.net as that domain is also assigned as the default domain for that IP in the IP Addresses section in the Server section in Plesk.

The first 2 ips are also used as shared ips for general domains that don't require a static ip or SSL.

My question is, with the second ip should I:

A) Setup the rdns to the name server assigned to that ip being ns2.mycompany.net

or

B) Just not have an rdns at all for that second ip

or

C) Setup the rdns for the default domain assigned to that ip under the IP Addresses section in the Server section in Plesk.

Thanks,

Matt

faris · Unread post by **faris** » Tue Jan 20, 2009 5:00 pm

By all means set up rdns for the second IP - you never know when you might need it, but it really does not matter what it is. Something with your domain in it would be nice. But it isn't going to get used for anything much.

laughingbuddha · Tue Jan 20, 2009 6:01 pm

Should the rdns be the name server? I'm finding mix results online in regards to this question.

Matt

faris · Unread post by **faris** » Tue Jan 20, 2009 6:15 pm

Never heard that in my life.

hostingguy · Unread post by **hostingguy** » Tue Jan 20, 2009 7:50 pm

personally I think RDNS should be the FQDN of the server

laughingbuddha · Tue Jan 20, 2009 9:26 pm

Ok, I won't. I just noticed on a domain tool that it checks if a name server has a rdns entry or not.

I have a domain setup on my servers first usable ip and a rdns entry setup with my server house for it.

Thanks,

Matt

faris · Unread post by **faris** » Wed Jan 21, 2009 7:05 am

hostingguy wrote:personally I think RDNS should be the FQDN of the server

Yes, but this is Matt's second IP. His first IP will be his FQDN (or similar).

Matt, I don't know for sure, but I think maybe the test you are looking at just wants ANY rdns for the IP of the nameserver, as opposed to one that matches the nameserver's "name"?

Which test is this anyway?

Bottom line: rdns is generally only important when it comes to email, and (currently) the two important things that you need with respect to this are:

1) To have rdns on the IP that your email server sends email out on (in Plesk with qmail this will normally be the IP in eth0:0 (usually the first IP you configure on your system)

2) For that rdns record to also forward resolve to an IP. 99% of the time the IP it resolves to does not have to be the same IP as the IP that email comes out on -- it just has to resolve forward and backward basically.

Faris.

laughingbuddha · Wed Jan 21, 2009 8:45 am

I'm using this site to run the tests:

http://www.pweb.cz/en/dns-test/dom.php

I have noticed differnt results when testing one of my domains compared to a client of mine who hosts with NuBlue.

For example, compare the results when testing themobilephonesite.com (NuBlue hosted) with unity101.org (I host). NuBlue has no rdns records for there name servers, where I have no rdns for the second IP that my second name server is on but I do for the first IP that the first name server is on.

Based on that, I suspect you're right. As long as there is an rdns on the IP, it doesn't really matter what the rdns resolves to, just as long as it does.

Makes sence I guess.

Thanks

Matt