What Exactly Causes "uid lease" Messages?

[Martin McCormick]

	While trouble-shooting a problem which turned out to be
caused by a miscommunication among people, I discovered a large
number of messages in syslog like:

Jun 13 13:40:43 ns dhcpd: uid lease 139.78.228.251 for client
00:1b:38:8d:b0:27 is duplicate on 139.78.228/22 
	Archive searches have turned up other people quoting
these messages, but I haven't found a good explanation as to
what is causing them 

	I thought they were related to the original problem I
was fixing, but I find them on all our campuses. All of them use
a dhcp failover pair and 2 of 3 sites are working fine. The
third appears to be fine but I am not totally satisfied yet.

	We had a case of someone not realizing that both DHCP
servers must see the same traffic so they didn't know that the
DHCP helper on the routers needed to point to both the primary
and secondary DHCP SERVERS.

	Our new failover pair worked for a whole month and a
half before things went so bad that my phone started to ring.
There were loads of "pere holds all free leases" messages as one
might expect.

	All that's left  that looks bad are  these "uid lease"
messages.

Martin McCormick WB5AGZ  Stillwater, OK 
Systems Engineer
OSU Information Technology Department Network Operations Group