forward name resolution OK, but reverse doesn't work ...

[Lyle Giese]

On 06/17/11 11:44, Thomas Schweikle wrote:
> Hi!
>
> I am having some problem with my nameserver:
>
> It resolves forward:
> !user at ks1:~$ host google.com
> !google.com has address 74.125.79.147
> !google.com has address 74.125.79.99
> !google.com has address 74.125.79.104
> !google.com mail is handled by 50 alt4.aspmx.l.google.com.
> !google.com mail is handled by 10 aspmx.l.google.com.
> !google.com mail is handled by 20 alt1.aspmx.l.google.com.
> !google.com mail is handled by 30 alt2.aspmx.l.google.com.
> !google.com mail is handled by 40 alt3.aspmx.l.google.com.
>
> But not reverse:
> !user at ks1:~$ host 74.125.79.99
> !Host 99.79.125.74.in-addr.arpa not found: 2(SERVFAIL)
>
> Main configuration (partly shorted):
> !options {
> !        directory       "/var/tmp/named";
> !        pid-file        "/var/run/named/named.pid";
> !        dump-file       "/var/run/named/named_dump.db";
> !        statistics-file "/var/run/named/named.stats";
> !        listen-on       { any; };
> !        #listen-on-v6   { any; };
> !        recursion yes;
> !        auth-nxdomain no;
> !};
> !
> !// slave to root name servers
> !zone "." {
> !  type slave;
> !  file "/var/cache/named/root/root.slave";
> !  masters { 192.5.5.241; };
> !  notify no;
> !};
> !
> !zone "arpa" {
> !  type slave;
> !  file "/var/cache/named/root/arpa.slave";
> !  masters { 192.5.5.241; };
> !  notify no;
> !};
> !
> !zone "in-addr.arpa" {
> !  type slave;
> !  file "/var/cache/named/root/in-addr.arpa.slave";
> !  masters { 192.5.5.241; };
> !  notify no;
> !};
> !
> !// RFC 1912 (and BCP 32 for localhost)
> !zone "localhost" {
> !  type master;
> !  file "/etc/named/master/localhost-forward.db";
> !};
> !
> !zone "127.in-addr.arpa" {
> !  type master;
> !  file "/etc/named/master/localhost-reverse.db";
> !};
>
> localhost-forward.db:
> !$TTL 3h
> !localhost. SOA localhost. nobody.localhost. 42 1d 12h 1w 3h
> !        ; Serial, Refresh, Retry, Expire, Neg. cache TTL
> !
> !        NS      localhost.
> !
> !        A       127.0.0.1
> !        AAAA    ::1
>
> localhost-reverse.db:
> !$TTL 3h
> !@ SOA localhost. nobody.localhost. 42 1d 12h 1w 3h
> !        ; Serial, Refresh, Retry, Expire, Neg. cache TTL
> !
> !        NS      localhost.
> !
> !1.0.0   PTR     localhost.
> !
> !1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0\
> ! PTR localhost.
>
> The server has AFAIS all root servers available:
> !$ORIGIN .
> !$TTL 86400      ; 1 day
> !@                     IN SOA  a.root-servers.net.\
> ! nstld.verisign-!grs.com. (
> !                                2011061700 ; serial
> !                                1800       ; refresh (30 minutes)
> !                                900        ; retry (15 minutes)
> !                                604800     ; expire (1 week)
> !                                86400      ; minimum (1 day)
> !                                )
> !                        RRSIG   SOA 8 0 86400 20110624000000 (
> !                                20110616230000 34525 .
> !                    kKIgiv5epNOi/mWtHYtH/Zwj6O6pV+wB09rnMiaTrYRk
> !                    HKqH7CCBdnIei6Kc1ghTRgdPwzrpgxzB3VHH/IfjEGbM
> !                    3sNGzMOYFtykMD1xjE93hBUU08yd1ojchWW2AXayGEJZ
> !                    5UOkaiA7cN3txThTtd1/r+k1zR5pvL+S6Pt7TTE= )
> !$TTL 518400     ; 6 days
> !                        NS      a.root-servers.net.
> !                        NS      b.root-servers.net.
> !                        NS      c.root-servers.net.
> !                        NS      d.root-servers.net.
> !                        NS      e.root-servers.net.
> !                        NS      f.root-servers.net.
> !                        NS      g.root-servers.net.
> !                        NS      h.root-servers.net.
> !                        NS      i.root-servers.net.
> !                        NS      j.root-servers.net.
> !                        NS      k.root-servers.net.
> !                        NS      l.root-servers.net.
> !                        NS      m.root-servers.net.
> !                        RRSIG   NS 8 0 518400 20110624000000 (
> !                                20110616230000 34525 .
> !                     KgMPA/Ucp/cFQHQ36kFe8lhVV6ckJx8Zk8Mm2aiKIxOB
> !                     v9fsM3qYyGOOqnNUGPr7V0X604r5xaePysUNy0iET+Ga
> !                     9WPmPeEX9438srt54qEDCBeCqn5Zbjo1lOVTrykAvtBI
> !                     Y8ONwpp0DcDw9D7mTyBzp+ARLVG56jaZ5AucyGQ= )
> [... havily shortened -- the file has about 211k length ...]
>
> Any idea, what is wrong here and where to change configuration to
> make reverse dns-lookups happen?
>
>

First of all, stop using host or nslookup.  Use dig.

Dig tells you alot more about what it did and even who gave it the 
answer it is trying to display.

Also try:

dig +trace -x 74.125.79.99

This is try to do a reverse lookup on this ip address and do a trace of 
it as it travels through various dns servers to get to the right answer.

I noticed that you have three zones defined '.' 'arpa' and 
'in.addr.arpa' showing 192.5.5.241 (f-root.servers.net) as the master. 
Are you getting zone transfers from there?

I question the need or a desire to have a copy of that zone on your dns 
server, let alone if you are getting a full zone from the F root.

Lyle Giese
LCR Computer Services, Inc.