What dns server do you use?
Also the named.conf file would be helpful.
This refers to bind, so if you use something else it won't work:
If you haven't already add an allow-update { ddnsclients; }; stanza to your zone definitions (where ddnsclients is an acl which you also have to define in the config file).
Then turn on some logging.
For debugging this particular problem add something along the lines of this to your named config file:
Code:
logging {
channel ddns {
file "/var/log/bind/updates.log versions 5 size 1m;
print-time yes;
print-category yes;
};
category update { ddns; };
};
Have some clients do the update and check the logs for any error messages.