Topic
  • 2 replies
  • Latest Post - ‏2009-06-15T04:45:01Z by SystemAdmin
SystemAdmin
SystemAdmin
134 Posts

Pinned topic Broken reverse DNS lookup

‏2009-06-12T08:20:42Z |
I have a name server for a class C subnet. Forward lookups work fine as does the reverse lookup for 127.0.0.1 However, reverse lookups for other hosts (i.e. when I used the class C address) do not work. There appears to be some problem with the SOA record or the zone. For example, here is the output for the reverse lookup of a host in the subnet.


$ dig -x 9.190.207.2   ; <<>> DiG 9.4.1 <<>> -x 9.190.207.2 ;; global options:  printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 350 ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0   ;; QUESTION SECTION: ;2.207.190.9.in-addr.arpa.      IN      PTR   ;; AUTHORITY SECTION: 207.190.9.in-addr.arpa. 3600    IN      SOA     bhadns01.au.ibm.com. qip.au1.ibm.com. 1617 600 300 604800 3600   ;; Query time: 4 msec ;; SERVER: 127.0.0.1#53(127.0.0.1) ;; WHEN: Sat Jun 13 05:00:18 2009 ;; MSG SIZE  rcvd: 127


The SOA in the AUTHORITY SECTION should point to my domain (system.au.ibm.com) not the superior domain.

I have attached the reverse lookup file for the subnet. Here is part of named.conf and rev.127.0.0


# primary 207.190.9.in-addr.arpa   rev.9.190.207 zone 
"207.190.9.in-addr.arpa" IN 
{ type master; file 
"rev.9.190.207"; 
};   # primary 0.0.127.in-addr.arpa     rev.127.0.0 zone 
"0.0.127.in-addr.arpa" IN 
{ type master; file 
"rev.127.0.0"; 
};     nimserver# cat rev.127.0.0 ; @       IN      SOA     nimserver.system.au.ibm.com. root.nimserver.system.au.ibm.com. ( 2007081400             ; Serial 3600            ; Refresh 300             ; Retry 3600000         ; Expire 86400 )         ; Minimum IN      NS      nimserver.system.au.ibm.com. 1       IN      PTR loopback. nimserver#


I suspect the problem is finger trouble (mine) but can't spot it. I would appreciate any assistance!
Updated on 2009-06-15T04:45:01Z at 2009-06-15T04:45:01Z by SystemAdmin
  • SystemAdmin
    SystemAdmin
    134 Posts

    Re: Broken reverse DNS lookup

    ‏2009-06-15T04:44:17Z  
    I thought that I would post the answer I discovered for the benefit of others.

    It turns out that in editing the reverse lookup file I had started a comment line with a colon instead of a semicolon. This fails silently or at least I could not find any error messages, only the manifestation that reverse lookup did not work.
  • SystemAdmin
    SystemAdmin
    134 Posts

    Re: Broken reverse DNS lookup

    ‏2009-06-15T04:45:01Z  
    I thought that I would post the answer I discovered for the benefit of others.

    It turns out that in editing the reverse lookup file I had started a comment line with a colon instead of a semicolon. This fails silently or at least I could not find any error messages, only the manifestation that reverse lookup did not work.