zero TTL

[Juerg Reese]

Hi

If it's a caching only server, then it has probably nothing
to do with DDNS. Only authoritative servers should accept DDNS
updates. The <zone-name>.log files are created by the name server
in the configured db files directory. You can grep for the hostname
you have problems with. But as said already, if it's a caching only
server I don't think the problem is there.

Check where your caching only server is forwarding to and check
if this server is answering correctly. With the zero TTL your
caching server does not cache the entry and therefore is always
forwarding.

regards,
Juerg

> -----Original Message-----
> From: LEE,TECK-MENG (HP-Singapore,ex1) [mailto:teck-meng_lee at hp.com]
> Sent: Friday, 6. October 2000 09:36
> To: 'reese at genesiscom.ch'; comp-protocols-dns-bind at moderators.isc.org
> Subject: RE: zero TTL
> 
> 
> Hi 
> 
> Thanks for your explanation. 
> 
> The DNS server 15.3.172.10 is definitely not authoritative
> for any zones as it is a caching name server. Thus, it could
> be due to some dynamic updates, but how do I check the *.log
> files? Is there any specific words that I can grep?
> 
> Also, how can I turn off dynamic updates to my name server?
> 
> Appreciate your help and time, thanks.
> 
> Regards
> Teck-Meng LEE
> 
> 
> 
> > -----Original Message-----
> > From: Juerg Reese [mailto:reese at genesiscom.ch]
> > Sent: Friday, October 06, 2000 12:15 AM
> > To: LEE,TECK-MENG (HP-Singapore,ex1);
> > comp-protocols-dns-bind at moderators.isc.org
> > Subject: RE: zero TTL
> > 
> > 
> > Hi 
> > 
> > Your Server at 15.3.172.10 seems to be authoritative
> > for hp-korea.net and has a wrong A record for
> > selrel1.hp-korea.net.
> > 
> > Is 15.3.172.10 Slave for hp-korea.net?
> > 
> > Check your db files on 15.3.172.10.
> > 
> > If the wrong entry could not be found in the
> > db file for hp-korea.net, one explanation could
> > be that your server received a DDNS update. This
> > would also explain the zero TTL. DDNS updates usually
> > have zero TTL.
> > 
> > Check for *.log files on your servers, there you
> > can check for DDNS updates.
> > 
> > regards,
> > juerg
> > 
> > ; <<>> DiG 8.1 <<>> selrel1.hp-korea.net
> > ;; res options: init recurs defnam dnsrch
> > ;; got answer:
> > ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 6
> > ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 0
> > ;; QUERY SECTION:
> > ;;      selrel1.hp-korea.net, type = A, class = IN
> > 
> > ;; ANSWER SECTION:
> > selrel1.hp-korea.net.   11h59m32s IN A  210.216.53.194
> > 
> > ;; AUTHORITY SECTION:
> > hp-korea.net.           11h59m32s IN NS  nis.dacom.co.kr.
> > hp-korea.net.           11h59m32s IN NS  ns2.dacom.co.kr.
> > 
> > ;; Total query time: 100 msec
> > ;; FROM: GPCBE-L02 to SERVER: default -- 10.10.1.11
> > ;; WHEN: Thu Oct 05 18:01:29 2000
> > ;; MSG SIZE  sent: 38  rcvd: 113
> > 
> > 
> > > -----Original Message-----
> > > From: news at cup.hp.com [mailto:news at cup.hp.com]On Behalf 
> Of Teck-Meng
> > > Sent: Thursday, 5. October 2000 10:29
> > > To: comp-protocols-dns-bind at moderators.isc.org
> > > Subject: zero TTL
> > > 
> > > 
> > > Hi
> > > 
> > > I have a problem here. Whenever I do a nslookup of 
> > > selrel1.hp-korea.net, my
> > > dns server will always return the same IP address; and this 
> > > IP address is
> > > wrong. All other DNS servers are able to return the correct 
> > > IP address,
> > > except for this particular one. Another thing is that this 
> > > answer that is
> > > returned by this DNS server is always authoritative.
> > > 
> > > I have extracted the dig output for your reference. Any help 
> > > is greatly
> > > appreciated. Thanks.
> > > 
> > > Btw, any idea why the answer for the TTL is 0S?
> > > 
> > > $ dig selrel1.hp-korea.net
> > > 
> > > ; <<>> DiG 8.2 <<>> selrel1.hp-korea.net
> > > ;; res options: init recurs defnam dnsrch
> > > ;; got answer:
> > > ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4
> > > ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, 
> > > ADDITIONAL: 2
> > > ;; QUERY SECTION:
> > > ;;      selrel1.hp-korea.net, type = A, class = IN
> > > 
> > > ;; ANSWER SECTION:
> > > selrel1.hp-korea.net.   0S IN A         128.88.255.170
> > > 
> > > ;; AUTHORITY SECTION:
> > > hp-korea.net.           12H IN NS       nis.dacom.co.kr.
> > > hp-korea.net.           12H IN NS       ns2.dacom.co.kr.
> > > 
> > > ;; ADDITIONAL SECTION:
> > > nis.dacom.co.kr.        12H IN A        164.124.101.31
> > > ns2.dacom.co.kr.        12H IN A        203.248.240.31
> > > 
> > > ;; Total query time: 69 msec
> > > ;; FROM: selrel1.hp.com to SERVER: default -- 15.3.172.10
> > > ;; WHEN: Thu Oct  5 16:11:28 2000
> > > ;; MSG SIZE  sent: 38  rcvd: 145
> > > 
> > > Regards
> > > Teck-Meng
> > > 
> > > 
> > > 
> > > 
> > > 
> > > 
> > 
>