in-addr.arpa cache corruption

[Mark_Andrews at isc.org]

> I was wondering if anyone ever found out what caused the problem in
> the trhead "Bind 8.2.3 cache corruption problem" back in May of last
> year.  I just ran into this problem on a Win2k SP2 server and thought
> it may have been something specific to Windows before I saw the thread
> indicating it had happened before with bind.  From my understanding,
> another DNS server (in this case, ipdns1.hinet.net and
> ipdns2.hinet.net) shouldn't be able to corrupt the cache for another
> domain (including in-addr.arpa).  Is this correct or do I have it
> completely wrong?

	Well the bad data shouldn't be there in the first place.
	This company is just being lazy.  That being said nameserver
	do attempt to catch garbage like this.

	Well if you use a forwarder the following applies.

1232.   [bug]           don't assume the forwarder has dropped bogus records.

> Any information would be helpful since I would like
> to make sure that it doesn't happen again.  I have included the output
> from dig below that shows that they have configured their servers to
> be authoritative for in-addr.arpa, but I still don't see how this
> information got into the cache on my DNS server.

	You needed to resolve a reverse record from a zone that was
	delegated to them.  The NS RRset was returned in the answer
	and cached.

	Mark

> 
> Thanks,
> Dave
> 
> <<>> DiG 8.3 <<>> @ipdns1.hinet.net in-addr.arpa soa
> ; (1 server found)
> ;; res options: init recurs defnam dnsrch
> ;; got answer:
> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 6
> ;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 2
> ;; QUERY SECTION:
> ;;      in-addr.arpa, type = SOA, class = IN
> 
> ;; ANSWER SECTION:
> in-addr.arpa.           1D IN SOA       hntp1.hinet.net.
> hostmaster.hinet.net.
>                                         200201040       ; serial
>                                         6H              ; refresh
>                                         2H              ; retry
>                                         5w6d16h         ; expiry
>                                         1D )            ; minimum
> 
> 
> ;; AUTHORITY SECTION:
> in-addr.arpa.           1D IN NS        ipdns1.hinet.net.
> in-addr.arpa.           1D IN NS        ipdns2.hinet.net.
> 
> ;; ADDITIONAL SECTION:
> ipdns1.hinet.net.       20h50m29s IN A  168.95.192.14
> ipdns2.hinet.net.       20h50m28s IN A  168.95.1.14
> 
> ;; Total query time: 152 msec
> ;; FROM: grape.juniper.net to SERVER: ipdns1.hinet.net  168.95.192.14
> ;; WHEN: Tue Jan  8 16:49:11 2002
> ;; MSG SIZE  sent: 30  rcvd: 166
> gain.
> 
--
Mark Andrews, Internet Software Consortium
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark.Andrews at isc.org