DDNS strangeness

Tom Parquette tparquet at twcny.rr.com
Sun Jul 13 14:10:28 PDT 2003

Hi.  I'm not sure if this belongs somewhere else but I'm starting here 
since these are 5.x systems.
Please CC me on any replies.  I subscribe to the digest format (makes 
replying difficult.)  TIA.

I have DDNS running between my house server and what will become an X 
They are both 5.x at different maintenance levels.
I have it updating the DNS server as I expect when I boot the X desktop.
If I have to boot the server, e.g. my town's unpredictable power, the X 
desktop machine cannot re-add itself to my DNS.
(DNS and DHCP run on the home server.  In this case, there is no third 
machine involved.)

I found a predictable way to get the X desktop to readd itself (by 
changing the hostname to something else then changing it back) but it 
did not feel right to me so I started rereading some of the man pages.

I found the following at the end of the "The Interim DNS Update Scheme" 
section of the dhcpd.conf man page:
"...So the DHCP server tracks whether or not it has updated the record 
in the past (this information is stored in the lease) and does not 
attempt to update records that it thinks it has already updated.

This can lead to cases where the DHCP server adds a record, and then the 
record is deleted through some other mechanism, but the server never 
again updates the DNS because it thinks the data is already there.  In 
this case the data can be removed from the lease through operator 
intervention, and once this has been done, the DNS will be updated the 
next time the cliend renews."

OK.  This description fits my scenario.  I understand it but I do not 
have to like it.

The statement "...the data can be removed from the lease through 
operator intervention..." is where I'm looking for some insights.
I reread the dhcpd man page looking for a manual way to alter the lease 
(to remove the DNS information.) 
The only thing I picked up on that MIGHT talk to this is OMAPI and the 
Lease Object.  The description if the Lease Object did not really help.

I understand that DDNS is not a standard (yet.)  I also know I'm sorta 
on my own here.
I was hoping someone had a workaround for this behaviour.

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