Reverse zone

Kevin Darcy kcd at daimlerchrysler.com
Mon Jun 4 21:42:28 UTC 2001


If you're sure you don't need reverse lookup capability, then don't bother
populating reverse zones with PTR records, but I think you would be
surprised at how many applications use reverse lookups (most of them
misguidedly, in my personal opinion). So you're probably
*generating* plenty of reverse lookups even if you don't *need* them. In
that case, not having reverse DNS at all may add latency to some of your
client/server connections, and if your DNS infrastructure is set up to
query for Internet names, you may be polluting the Internet
DNS infrastructure with unnecessary reverse lookups. For this reason, you
may want to set up reverse DNS privately even if nothing on your network
actually needs it. Setting up an "empty" in-addr.arpa zone (nothing but
SOA and NS records for the zone itself) should be enough to make all
reverse lookups return NXDOMAIN very quickly (especially if all of your
nameservers are master or slave for this same "empty" zone)...


- Kevin

Rok Pergarec wrote:

> Hi,
>
> I'm having problems with reverse zone. First of all, should I have a
> reverse zone like ip.in-addr.arpa if my network doesn't support reverse
> lookups for any reason?
>
> so I have the
>
> zone "my.ip.in-addr.arpa" in {
>          type master;
>          file "/var/named/pz/my.ip";
> };
>
> in my named.conf... my.ip file looks like this:
>
> $TTL 1D
>
> @               IN      SOA     my.domain. root.my.domain. (
>                            2000106039    ; serial
>                            8H            ; refresh, seconds
>                            2H            ; retry, seconds
>                            1W            ; expire, seconds
>                            1D )          ; minimum, seco
>
>                          NS              my.domain.
>                          NS              my.sec.server.
>
> 1                       PTR             dns.my.domain.
>
> Since I'm new to bind I don't really know how does this works... in
> other words.. in don't undrstand the PTR records...
>
> Thanks in advance.
> Rok





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