FAQ Search Today's Posts Mark Forums Read
» Video Reviews

» Linux Archive

Linux-archive is a website aiming to archive linux email lists and to make them easily accessible for linux users/developers.


» Sponsor

» Partners

» Sponsor

Go Back   Linux Archive > CentOS > CentOS

 
 
LinkBack Thread Tools
 
Old 04-13-2010, 10:07 PM
"Hugh E Cruickshank"
 
Default Disappearing DNS entry

CentOS 4.8, BIND 9.2.4, DHCP 3.0.1

Hi All:

I have a rather perplexing problem where the DNS entry in BIND for
one of my network printers sporadically "disappears" from our zone
file (but not the reverse zone file). We have four Lexmark printers
connected locally over our internal LAN using static IP addresses.
We have 3 T640n printers and a T642n printer and it is only the
T642n printer that this is happening to.

I thought I had it licked when I discovered that both DDNS and mDNS
were enabled on this printer but not the others, however disabling
those has had no effect.

We do use DHCP for the bulk of our Windows workstations and DHCP
is configured to update the DNS server and this appears to work fine
(once I disabled all the "Register this connection's address in DNS"
options on the workstations).

I have found one suspicious entry in /var/log/messages:

Apr 12 17:34:14 fisds0 named[5210]: client 192.168.2.7#10242: updating
zone 'forsoft.com/IN': deleting an RR

This would seem to indicate that the printer itself has issued the
request to the DNS server but for the life of me I cannot see what
might be doing it.

Has anyone encountered something similar and can point me in the right
direction?

TIA

Regards, Hugh

--
Hugh E Cruickshank, Forward Software, www.forward-software.com
_______________________________________________
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos
 
Old 04-13-2010, 10:29 PM
"Hugh E Cruickshank"
 
Default Disappearing DNS entry

From: Hugh E Cruickshank Sent: April 13, 2010 15:07
>
> I have found one suspicious entry in /var/log/messages:
>
> Apr 12 17:34:14 fisds0 named[5210]: client 192.168.2.7#10242: updating
> zone 'forsoft.com/IN': deleting an RR
>
> This would seem to indicate that the printer itself has issued the
> request to the DNS server but for the life of me I cannot see what
> might be doing it.

One additional piece of information... It appears that I had not set
the DNS server and NTP server correctly on all four printers and they
were running with a very old date (would you believe 1970?). I have
since ensured that all four printers now have the correct DNS server
IP address, the host name of our local NTP server, the correct time
zone and that they all now have the correct current date and time via
NTP.

I am not sure if this would have had anything to do with the DNS issue
but it was something that was obviously wrong and needed to be fixed.

Regards, Hugh

--
Hugh E Cruickshank, Forward Software, www.forward-software.com
_______________________________________________
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos
 
Old 04-14-2010, 12:01 AM
Jim Perrin
 
Default Disappearing DNS entry

On Tue, Apr 13, 2010 at 6:07 PM, Hugh E Cruickshank <hugh@forsoft.com> wrote:

> I have found one suspicious entry in /var/log/messages:
>
> Apr 12 17:34:14 fisds0 named[5210]: client 192.168.2.7#10242: updating
> * * * * * * * *zone 'forsoft.com/IN': deleting an RR
>
> This would seem to indicate that the printer itself has issued the
> request to the DNS server but for the life of me I cannot see what
> might be doing it.

This means a couple things. First, your zone is configured to allow
dynamic DNS updates, which can be okay, but usually you don't want
this for a zone containing fixed records.

Second, it means that client updates is allowed. This can be bad, and
generally when I set up dynamic DNS zones, I only allow updates from
the dhcp server (usually the same box, so it's restricted to localhost
doing the updating).

Essentially your printer is trying to update its record and removing
the old one, but not publishing the right one, either through
permissions or some other reason.

> Has anyone encountered something similar and can point me in the right
> direction?

How do you have your zones and/or dhcp server configured? Can you
sanitize them enough to post them?

--
During times of universal deceit, telling the truth becomes a revolutionary act.
George Orwell
_______________________________________________
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos
 
Old 04-14-2010, 02:26 AM
"Hugh E Cruickshank"
 
Default Disappearing DNS entry

From: Jim Perrin Sent: April 13, 2010 17:01
>
> This means a couple things. First, your zone is configured to allow
> dynamic DNS updates, which can be okay, but usually you don't want
> this for a zone containing fixed records.

That was intentional on my part. We have a small network and I did not
see any compelling reason not to do it that way. I will look at
separating these out in the future.

> Second, it means that client updates is allowed. This can be bad, and
> generally when I set up dynamic DNS zones, I only allow updates from
> the dhcp server (usually the same box, so it's restricted to localhost
> doing the updating).

Again intentional but no longer required. In reviewing the config files
in response to your comments I see that had allowed update to the zone
file from the entire subnet while only "key rndckey" for the reverse
zone files. That would explain why only the zone file was affected and
not the reverse files. I have fixed that now and I think that should
resolve my problem.

> Essentially your printer is trying to update its record and removing
> the old one, but not publishing the right one, either through
> permissions or some other reason.

Sounds valid.

> How do you have your zones and/or dhcp server configured? Can you
> sanitize them enough to post them?

I will hold off for now as I believe the change that I have made to
named.conf will now avoid the problem. I still do not know why only
the one printer was affected but the change should avoid the problem.
Some day when I have some free time (yeah right!) I am try to figure
what the actual cause is.

Thanks very much for your comments, they are greatly appreciated.

Regards, Hugh

--
Hugh E Cruickshank, Forward Software, www.forward-software.com
_______________________________________________
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos
 

Thread Tools




All times are GMT. The time now is 10:47 AM.

VBulletin, Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Relevant URLs by vBSEO ©2007, Crawlability, Inc.
Copyright 2007 - 2008, www.linux-archive.org