DDNS Updates

[Kleinfeld, Ralf]

Hi,
I am trying to find out more about how exactly ddns workds from the dhcp
server
point of view.

If a clients receives an ip adress and the servers is configured to do the
updates,
what exactly happens there.

I went through "The DHCP Handbook", but found no deep technical description
of what happens.

As far as I see in the log, it's looking for an existing A Record for the
clients name.
Furthermore it looks for a TXT records.

What is exactly the meaning of the string value of the TXT records, which is
created
along with an A record?


Furthermore, I have noticed that the dhcp server is NOT updating an A
record, if the
appropriate TXT record is missing. Is there a way to "force" the dhcp server
to touch
the record?

What event forces the dhcp server to update DNS? Is it only happening on
behalf of 
a DISCOVER-OFFER-REQUEST-ACK or also on a renew within the leasetime?

Regards,
Ralf