a bit of theory about PTR records requested
maillist at blitzen.net
Wed Mar 29 16:52:19 UTC 2000
what is the difference between A and the PTR ?
i can see that one does the opposite of of the other
but what does the A and the PTR stand for?
On Wed, 29 Mar 2000, Gregg Rosenberg wrote:
> If we are talking external address space. Any address not actually being
> used for accessing a machine on the inside or any address used for NAT is
> given a generic name. You definitely must have an external reverse for
> Here you could try a wild card PTR. Although I don't like that method. My
> preference is to setup generic names that can be easily script or
> spreadsheet generated for both the forward and reverse.
> host-64-4-192-1 IN A 22.214.171.124
> host-64-4-192-2 IN A 126.96.36.199
> host-64-4-192-3 IN A 188.8.131.52
> 184.108.40.206 IN PTR host-64-4-192-1.
> 220.127.116.11 IN PTR host-64-4-192-2.
> 18.104.22.168 IN PTR host-64-4-192-3.
> You can make the names as simple or complex as you like.
> At 08:26 AM 03/29/2000, Martijn van Katwijk wrote:
> >At 15:44 29-3-00, Gregg Rosenberg wrote:
> >>With the address range you are showing, I will assume that we are looking
> >>at an internal DNS for address space behind your firewall.
> >No, i'm sorry, it was meant to be an example. Wrong example...
> >I'm deleting a lot of PTR records now (one PTR per IP), so i'm happy. I
> >know what to do.
> >>There are slight performance advantages to setting up reverses. If your
> >>users are not connecting to any services on the inside that require
> >>reverse authentication it likely does not matter. I personally consider
> >>it a good practice to do. Depending on your environment there are
> >>different ways to approach this. If you are running a DHCP server with
> >>statically assigned leases, you can dump your DHCP table into Excel (or
> >>some other favorite spreadsheet tool) and use a macro to make the reverse
> >>file. You could write a script to convert your forward into a reverse
> >>and run it each time you make a change. (one may exist on the net,
> >>although I don't personally no of it. The other option might be to
> >>consider using dynamic DNS with DHCP. This is still a bit new and likely
> >>will require patience and testing. I hope these ideas are helpful.
> >>At 03:33 AM 03/29/2000, Martijn van Katwijk wrote:
> >>>I also have zones like this:
> >>>domain.com. IN A 192.168.1.60
> >>>www IN CNAME domain.com.
> >>>In fact I have quite a lot of these, all pointing to a single virtual
> >>>name based webserver with only a few IP nrs assigned to it.
> >>>So I have a lot of A records to a single IP nr.
> >>>Do I have to configure a PTR for each A record? Or is that meaningless.
> >>Gregg Rosenberg -- N9NNO
> >>RICIS, Inc.
> >>gregg at ricis.com
> >>"Obstacles are those frightful things you see when you
> >>take your eyes off your goals." Author unknown
> >Martijn van Katwijk
> >AAA on Internet
> >info at aaa.nl
> >+31 342 418225 (Tel)
> >+31 342 423568 (Fax)
> Gregg Rosenberg -- N9NNO
> RICIS, Inc.
> gregg at ricis.com
> "Obstacles are those frightful things you see when you
> take your eyes off your goals." Author unknown
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