Solved

Multiple PTR records?

Posted on 2010-08-19
7
932 Views
Last Modified: 2013-11-25
Hello

I had a question re. DNS I was hoping someone could help me out with.

i) Is it possible for a host to have more than PTR record?
ii) Is it possible for an IP address to have more than one A record?

The answers should be relevant to:

i) Microsoft AD DNS
ii) UNIX DNS (QIP)
iii) WINS

Many thanks!
0
Comment
Question by:kam_uk
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
  • 3
7 Comments
 
LVL 74

Assisted Solution

by:Glen Knight
Glen Knight earned 100 total points
ID: 33478394
An IP Address can have as many A records as you like.
you can also have more than one PTR records, why you would want to I don't know.
0
 
LVL 3

Author Comment

by:kam_uk
ID: 33478677
Hi Demazter

Thanks..

If I didn't have access to the DNS system itself, do you know how I can find out what those multiple values were? I assume if I used PING and NSLOOKUP, I would only be returned one value at a time?
0
 
LVL 26

Expert Comment

by:DrDave242
ID: 33486912
Ping will only return one address, but nslookup will list them all.
0
NFR key for Veeam Agent for Linux

Veeam is happy to provide a free NFR license for one year.  It allows for the non‑production use and valid for five workstations and two servers. Veeam Agent for Linux is a simple backup tool for your Linux installations, both on‑premises and in the public cloud.

 
LVL 3

Author Comment

by:kam_uk
ID: 33513239
Thanks, but what command would I need for NSLOOKUP to list them all?

Just

NSLOOKUP <IP>

?
0
 
LVL 26

Accepted Solution

by:
DrDave242 earned 400 total points
ID: 33515548
I prefer to use nslookup in interactive mode, but I've been doing some testing, and here's what I've found:

(Note that these tests were performed on a Windows 2003 R2 DC.  It's possible that 2008 and/or 2008 R2 will give different results, and I know next to nothing about UNIX, BIND, or anything of that sort.)

"Nslookup <hostname>" will return all IP addresses in host records with that name.
Nslookup in interactive mode (ie., typing "nslookup" <Enter> "<hostname>" <Enter>) will do the same.
"Nslookup <IP_address>" will only return one hostname for that address.
Nslookup in interactive mode does two things: If you simply enter interactive mode and then type the IP address, it will only return one hostname.  However, if you explicitly set the query type to PTR ("set q=ptr" in interactive mode) and then enter the IP address, it will return all PTR records with that address.  There's probably a way to set the query type in non-interactive mode as well, but being a fan of interactive mode, I don't know of it.
0
 
LVL 3

Author Comment

by:kam_uk
ID: 33516239
Thanks... Just to be sure what you mean about interactive mode for multiple PTR returns, would be something like this:

Nslookup

Set type=ptr

0
 
LVL 26

Expert Comment

by:DrDave242
ID: 33516254
That's it exactly.
0

Featured Post

What is SQL Server and how does it work?

The purpose of this paper is to provide you background on SQL Server. It’s your self-study guide for learning fundamentals. It includes both the history of SQL and its technical basics. Concepts and definitions will form the solid foundation of your future DBA expertise.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Auditing domain password hashes is a commonly overlooked but critical requirement to ensuring secure passwords practices are followed. Methods exist to extract hashes directly for a live domain however this article describes a process to extract u…
Microsoft Office 365 is a subscriptions based service which includes services like Exchange Online and Skype for business Online. These services integrate with Microsoft's online version of Active Directory called Azure Active Directory.
Are you ready to implement Active Directory best practices without reading 300+ pages? You're in luck. In this webinar hosted by Skyport Systems, you gain insight into Microsoft's latest comprehensive guide, with tips on the best and easiest way…
There are cases when e.g. an IT administrator wants to have full access and view into selected mailboxes on Exchange server, directly from his own email account in Outlook or Outlook Web Access. This proves useful when for example administrator want…

635 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question