dhcpd and no dns update

Simon Hobson dhcp at thehobsons.co.uk
Thu Mar 16 14:08:03 UTC 2006

Danilo Levantesi wrote:

>I'm experiencing a problem with dhcpd and dns update.
>I have bind condigured and I would like dhcpd sends dns update to bind server,
>but i can not have this working.
>The dhcpd's logs show no dnsupdate activity, and bind's log neither.
>Moreover, using "netstat -a -n|grep 953" I can not see any TIME_WAIT
>connection on 953 port, but only a 953 LISTENING state.
>Can someone help me?

See below.

># dhcpd.conf
>ddns-updates on;
>ddns-update-style interim;

Since this is not a 'real' domain, there is no way for the dhcp 
server to find the master - so you need to tell it via a zone 

>ddns-ttl 7200;
>option subnet-mask;
>option broadcast-address;
>option routers;
>option domain-name "engineers";
>option domain-name-servers;
>ddns-hostname = pick (option fqdn.hostname, option host-name, concat
>("host",binary-to-ascii (10, 8, "-", leased-address)));
>option host-name = config-option server.ddns-hostname;
>subnet netmask {
>         range;
>         ignore client-updates;
>         key DHCP_UPDATER {
>                 algorithm HMAC-MD5;
>                  secret "SsgpQcPM4Q4EJexV7TWj7Q==";
>         }
>         zone engineers. {
>              primary;
>              key DHCP_UPDATER;
>         }

But of course, here is the zone statement - hidden within the subnet 
declaration which might be why it isn't working.

>         zone 254.168.192.in-addr.arpa. {
>              primary;
>              key DHCP_UPDATER;
>         }
>         host antartic {
>                 hardware ethernet 00:11:2f:70:ae:59;
>                 fixed-address;
>                 option host-name "antartic";
>                 ddns-hostname "antartic";
>         }

I really should make a template rant for this, host statements are 
global in scope, they should not be put within a subnet declaration 
as it will cause confusion.



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