F23 does not renew dhcp leases correctly and corrupts DDNS

[Greg Woods]

On Mon, Jan 25, 2016 at 5:39 AM, Dr J Austin <ja at jaa.org.uk> wrote:

> Jan 25 10:26:38 maui dhcpd: Forward map from paxos.jaa.org.uk to
> 148.197.29.131 FAILED: Has an address record but no DHCID, not mine.


This message means that the DHCP server checks DNS and finds there is
already an A record for paxos.jaa.org.uk, but there is no matching TXT
record to show that this A record was made by this DHCP server. For
example, my workstation at work:

# dig snowcrash.scd.ucar.edu any
[comments deleted]
snowcrash.scd.ucar.edu. 3600 IN A 128.117.10.112
snowcrash.scd.ucar.edu. 3600 IN TXT "<long ugly hex string>"

When a workstation comes online and requests an address, the DHCP server
will update the DNS, assuming that the TXT record exists and has a value
that shows it was made by the same DHCP server that is trying to do an
update. The "no DHCID, not mine" message means the A record is there but
the TXT record is not, therefore the DHCP server doesn't believe it has the
authority to delete the A record and install a new one.

The only way I've found to fix this is to use something like nsupdate(8) to
delete the offending A record, then reconnect the workstation. That should
cause the correct A and TXT records to be added to DNS. If you have a small
zone that doesn't change often, another option might be to get the DNS
server to dump the current zone, edit that dumped zone to remove the
offending A record, move the ".jnl" file out of the way, put the edited
zone file in to the place declared in the "file" parameter for this zone in
named.conf, then reload the DNS server. (I can't remember how to get a dump
of the zone, but I remember doing it in the past. Since we have a very busy
DHCP server at work, I always just use nsupdate(8) to modify the active
zone).

--Greg
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.fedoraproject.org/pipermail/users/attachments/20160125/6e3b0d6b/attachment.html>