Antwort: DDNS and DHCP updates failing

holger.honert at holger.honert at
Thu Jan 13 06:34:17 UTC 2005

Hi Gareth,
to get more infos please put the following line in your dhcpd.conf:

log-facility local1;

and configure your syslogd corrensponding to that., e.g. 

local1.debug                     /var/log/dhcpd.log

Maybe you will find more output for troubleshooting!


Kind Regards/Freundlichen Gruß
Holger Honert
Joseph-Scherer-Str. 3
44139 Dortmund
Phone: +49 231/135-4043
FAX: +49 231/135-2959
mailto: holger.honert at

ccx264 at (Gareth Ansell)
Gesendet von: bind-users-bounce at
12.01.2005 12:45
An:           comp-protocols-dns-bind at
Thema:        DDNS and DHCP updates failing


This may be a bit off topic, as it is to do with ISC dhcpd, not bind,
but I couldn't find a group for dhcpd, and the topics are closely

We have a DHCP/DDNS setup (bind-9.2.3 and dhcp-3.0pl2 on a slackware
which has been working OK, but it has now stopped. There have been no
updates to the servers, and no modifications (which I know of) to the
configuration files.

The problem appears to be that DHCP is no longer sending out update
messages to the DNS server.  The DNS server appears to be working OK,
and will update using nsupdate OK.  The really curious thing about
this is, that if you grep the log files, the DHCP does do the
occasional update, about 1 a day or so.  However, it should be doing
much much more than this.

This is an example from the named.conf file

zone "" {
        type master;
        file "dhcp/dhcp.coventry";
        allow-update {localhost; key DHCP-DNS.;};
        allow-transfer { key dns1-dns2.;;;  };

This is what we have in the dhcpd.conf for the above zone

ddns-updates true;
ddns-update-style interim;
ddns-domainname "";
ddns-hostname = pick(host-decl-name, option host-name);
ddns-ttl 86400;
deny client-updates;

zone {
        key DHCP-DNS.;

I have turned on the debugging for named, which showed that it was
not receiving any update messages, and a tcpdump showed that none
were being send by dhcp.

Has anyone experienced this before?  Does anyone know how to ramp
up the logging on the DHCP server to try to get any more info, is
this a really obvious config problem which I am missing?

Any help greatly appreciated.

Gareth Ansell

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