ddns-hostname problems - DDNS updates not sent

Daniel Pocock daniel at pocock.com.au
Fri Jul 5 16:46:14 UTC 2013

Package: isc-dhcp-server
Version: 4.2.2.dfsg.1-5+deb70u6
Severity: important

I've found that DDNS updates are only sent if ddns-hostname is
statically defined, e.g.

ddns-hostname "some-name";

Of course, this is not useful because dhcpd will then use the value
"some-name" as the hostname of every host and the real hostnames won't
be in DNS at all.

On the client side, I've tried many different permutations, for example,
the Debian default is to send

send host-name = gethostname();

but I've also tried commenting that out and using:

send fqdn.fqdn "hostname.example.org."
send fqdn.encoded on;
send fqdn.server-update off;
also request fqdn, dhcp6.fqdn;

but it doesn't make any difference.

On the server side, I tried various permutations as well:

- not setting ddns-hostname at all

ddns-hostname = pick (option fqdn.hostname, option host-name);

and various other things I've seen in examples, such as

option host-name = config-option server.ddns-hostname;

option server.ddns-domainname = config-option host-name;

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