dhcp deletes ddns entry
craig5 at pobox.com
Wed Jun 20 20:32:41 UTC 2007
I spoke too soon. The problem is still there.
> I know this was a while ago... but I just upgraded it and everything
> seems to be working better. (The clients require a release and renew,
> but DDNS seems to pick things up.) I'll need to let things settle for a
> few days to make sure, but so far so good.
> And thanx for the info on the update algorithm.
> Simon Hobson wrote:
>> Craig wrote:
>>> We have one machine (Linux: CentOS 4.4; dhclient v3.0.1) that has it's
>>> ip address dynamically allocated by dhcpd (v3.0.1). But, the DHCPREQUEST
>>> will trigger the DNS entry (via DDNS) to be deleted.
>>> At 8:41, the client (CENTOS_CLIENT) appears to do a DHCPREQUEST, at
>>> which time the dhcpd server seems to verify that the RR does exists and
>>> then deletes it. (Shouldn't it do an update?)
>>> Then the next time the client does a DHCPREQUEST (9:45), the RR does not
>>> exists and is, obviously, added.
>>> But, in the interim, the client name does not exists in DNS.
>>> I am running a slightly older version of dhcpd (3.0.1), but I can't find
>>> anything in the release notes that say this is fixed in 3.0.5. Also,
>>> some simple web searches did not find anything.
>> 3.0.1 isn't "slightly older", it's ancient ! Upgrade and see if the
>> problem is still there.
>> As to "Shouldn't it do an update?", well no it doesn't work that way.
>> The algorithm is something like :
>> If update required (ie lease database says it hasn't been done)
>> if client hasn't said it will do forward updates
>> do forward update
>> do reverse update
>> The forward update is done by
>> if (both A record and matching TXT record exist) then delete A record,
>> delete TXT record, create new A record, delete new TXT record.
>> The reverse update is done by
>> delete PTR record(s), create PTR record.
>> It's just simpler to delete any existing record(s) and create new ones
>> rather than work through all the permutations of possible updates.
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