Multiple DHCP Servers with DDNS Best Practice/Workaround?
dhcp1 at thehobsons.co.uk
Thu May 12 17:02:01 UTC 2011
Colin Simpson wrote:
> > To avoid this you would either need to prevent deletion of the DNS
>> entries (in which case you'd need to come up with some means of
>> garbage collection), or modify the code to not delete entries if the
>> A record doesn't match what the server thinks it added. The latter
>> would probably work, but it's more code hacking.
>Surely Server B can happily replace the DNS entry placed there by server
>A. Then when Server A expires the original lease it should realise that
>the DNS entry (the A record for the client) wasn't the one it put in
>there (i.e doesn't match the IP in the A record doesn't match it's
>leases file) and should leave it alone? It should still remove the
>reverse PTR record to keep things tidy.
>So no communication should be necessary.
>Or am I missing something?
Only reading the last sentence I wrote !
Thinking some more, it may be worth checking the exact update command
used in the current code. If the deletion is of "any A record
belonging to <FQDN>" then things will break. On the other hand, it's
quite possible the deletion command could be to delete a specific A
record - in which case server A would in fact leave the record alone.
Having failed to delete the A record, it may well then not try to
delete the PTR record either. It will however scatter error messages
throughout the logs.
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