Take the 2-minute tour ×
Server Fault is a question and answer site for professional system and network administrators. It's 100% free, no registration required.

I own a typical shared IP hosting plan and domain. I can modify the DNS of the domain from the control panel. The mailserver shares the same IP address, so my typical DNS config is:

www.mydomain.com   A      -> myIP
mydomain.com       A      -> myIP
ftp.mydomain.com   A      -> myIP
mail.mydomain.com  A      -> myIP
mydomain.com       MX(10) -> myIP

I read some Q&A on this site where they suggest to add PTR record mainly for mailserver.

I would like to add PTR record to my domain, I have got two questions:

1) can PTR record be added even if the hosting/mailserver are on a shared IP address? Or do I need a dedicated IP.

2) How do I setup PTR record, I mean does it look like A record:

mydomain.com (PTR) -> myIP
share|improve this question
add comment

3 Answers 3

up vote 2 down vote accepted

You can't create a PTR record for the ip address in your domain name DNS zone. The PTR record needs to be created in the rDNS zone by the owner of the netblock that encompasses your ip address. You'll need to speak to whomever you get the ip address from and ask them to create a PTR record for you.

share|improve this answer
    
So why mydomain.com DNS control panel lets me add PTR records? –  Marco Demaio May 6 '10 at 14:07
add comment

You can only set up a PTR record if you are the delegated maintainer of the relevant portion of the in-addr.arpa. domain name.

In your case that would be your web host. If you have a dedicated IP address then they should allow you to request the appropriate entry. On the other hand, if you have a shared IP address then it's very unlikely that they would permit this.

For what it's worth, if your mail server is called mail.example.com and its IP address is w.x.y.z then the appropriate DNS record would look like:

z.y.x.w.in-addr.arpa. IN PTR mail.example.com.
share|improve this answer
    
Hmmm, so what happens if I add in the DNS record of mydomain.com: "myip.in-addr.arpa IN PTR mail.mydomain.com" actually the DNS control panel let me do this, but is then useless? –  Marco Demaio May 6 '10 at 13:26
    
you can't do that - it's illegal. Note the trailing '.' on 'in-addr.arpa.'. That's a full qualified domain name, in a separate zone, so you can't possibly add it to 'myexample.com'. –  Alnitak May 6 '10 at 14:20
add comment

PTR should be the server name, which also should have an IN A entry. Whether PTR can be added is TOTALLY up to the host -whether he allows you to or not. THat said, SMTP without matching PTR is kind of stupid (you get LOTS of rejects).

How you set that up - well, dont ask here... ask you host. Because the host can tell you how o set it up ON HIS CONTROL PANEL ;)

share|improve this answer
    
Thnaks, I know how to use the control panel but could someone expalin what record do I need to add in order to place a PTR record. Let's simply say I have the domain "mydomain.com" that point to IP "myip" –  Marco Demaio May 6 '10 at 11:13
    
I dont know because I don'T even know what control panel. I suggest you just contact your hoster support. They will be able to help you out. –  TomTom May 6 '10 at 11:47
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.