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PTR and IPTables

By vandervyvere ·
What is PTR? I know it has something to do with reverse DNS'ing. How can I set PTR records to point to my DNS server on my network

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by p.j.hutchison In reply to PTR and IPTables

Yes, you can set up Reverse DNS (ie get a name from an IP address). There is no additional setup required.
You can use this feature when using PING -A address or NSLookup to find out names from IP addreses.

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by cpfeiffe In reply to PTR and IPTables

In your DNS server you need a zone for the PTR records. For example, if your A record (maps hostname to IP) is 'server1 IN A 1.2.3.4' you might want a zone that is 3.2.1.in-addr.arpa and in it you would have a recor that reads '4 IN PTR server1'. That way when someone does 'nslookup 1.2.3.4' they will know that the IP belongs to server1. If you are managing DNS through a GUI tool some of them have a check box for 'create ptr record' when you are creating your A record. Also, if the zone is there and the systems you are looking to maintain in are set to do DDNS (dynamic dns) updates and the DDNS feature is enabled on your DNS server the A and PTR records will be updated automatically.

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by Nico Baggus In reply to PTR and IPTables

There might be a problem when you want the PTR's
on the internet though. There you probably need
to convince your ISP that the PTR's need to get
updated. They might not want to do that.
In that case you will be stuck with
adls-1-2-3-.xyzisp.net or something like that.
It might be that you don't own a whole class C
subnet (256 addresses) and in that case your
provider needs to set you up with a subnetted
range (not easily done in all DNS servers) or
you have non-fixed addresses ....

You need to fix this with you ISP ...

Kind regards,

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by thanetadmin In reply to PTR and IPTables

You can have secondary DNS servers inside your network. If you need to PTR records, contact your ISP for SOA permission .

Thanks,
kias

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For easy setup

by D.ane In reply to PTR and IPTables

A PTR record is a pointer record from an IP address to a hostname. A lookup only returns the hostname.

If you need to set this up on your own server, you first need to have the IP address delegated to your server. If this is not an option (ISP owns the IP) ask for them to Cname a hostname in your zone, where you setup the PTR record.

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