Need help troubleshooting log messages

Carlos Vicente cvicente at network-services.uoregon.edu
Fri Apr 4 16:21:50 UTC 2008


Timothy Holtzen wrote:
> Hi all.  I'm somewhat new to ISC dhcp and don't quite know what to
> make of some messages I'm getting in my logs:
>
> uid lease 10.12.1.165 for client 00:17:f2:dc:c5:41 is duplicate on
> 10.12/16: 1 Time(s)
> uid lease 10.12.1.198 for client 00:17:f2:e0:4d:a5 is duplicate on
> 10.12/16: 1 Time(s)
> uid lease 10.12.2.192 for client 00:17:f2:dc:c5:41 is duplicate on
> 10.12/16: 1 Time(s)
> uid lease 10.17.1.161 for client 00:1b:63:1e:ac:49 is duplicate on
> 10.17/16: 1 Time(s)
> uid lease 10.17.1.99 for client 00:1b:63:1e:ac:49 is duplicate on
> 10.17/16: 1 Time(s)
>
> Googling about it would appear that these messages are usually the
> result of a misconfiguration of the server when  overlapping pools are
> setup or a host entry is setup with an IP number within a pool.   I've
> double checked that my pools for these subnets don't overlap and none
> of these clients is listed in any host entry.  Does anyone know what
> might be causing these messages or how I might go about
> troubleshooting them?  I tracked down the first client listed and it
> doesn't appear to be having any problems with IP conflicts or the
> like.  It does however appear over time that the client gets the IP
> 10.12.2.192 for a while and uses it and then gets the IP 10.12.1.165
> and uses it for a while but not both at the same time.  Could it be
> these clients are simply requesting a new lease each time rather than
> renewing their existing one?  If so why would they do that?  Any help
> would be appreciated even if you can just point me at the right
> documentation or web site posting.
> I'm running dhcp-3.0.5-7.el5 under RHEL 5.
>

I'm having similar issues that I do not quite understand.  I just
counted 140 individual hosts that show the 'is duplicate' line since
early this morning.
Here's the sequence of events for a particular host on both servers
(failover setup with v 3.1.0):

Apr  4 07:44:11 server1 dhcpd: DHCPDISCOVER from 00:a0:d1:72:05:62 via
10.20.190.2
Apr  4 07:44:12 server1 dhcpd: DHCPOFFER on 10.20.190.163 to
00:a0:d1:72:05:62 (Owner-PC) via 10.20.190.2
Apr  4 07:44:15 server1 dhcpd: DHCPDISCOVER from 00:a0:d1:72:05:62
(Owner-PC) via 10.20.190.2
Apr  4 07:44:15 server1 dhcpd: DHCPOFFER on 10.20.190.163 to
00:a0:d1:72:05:62 (Owner-PC) via 10.20.190.2
Apr  4 07:44:15 server1 dhcpd: DHCPREQUEST for 10.20.190.163
(10.20.32.35) from 00:a0:d1:72:05:62 (Owner-PC) via 10.20.190.2
Apr  4 07:44:15 server1 dhcpd: DHCPACK on 10.20.190.163 to
00:a0:d1:72:05:62 (Owner-PC) via 10.20.190.2
Apr  4 07:44:19 server1 dhcpd: DHCPACK to 10.20.190.163
(00:a0:d1:72:05:62) via eth0
Apr  4 07:45:23 server1 dhcpd: DHCPACK to 10.20.190.163
(00:a0:d1:72:05:62) via eth0
Apr  4 07:47:28 server1 dhcpd: DHCPACK to 10.20.190.163
(00:a0:d1:72:05:62) via eth0
Apr  4 07:50:16 server1 dhcpd: DHCPACK to 10.20.190.163
(00:a0:d1:72:05:62) via eth0
Apr  4 07:51:45 server1 dhcpd: DHCPREQUEST for 10.20.190.163 from
00:a0:d1:72:05:62 (Owner-PC) via eth0
Apr  4 07:51:45 server1 dhcpd: DHCPACK on 10.20.190.163 to
00:a0:d1:72:05:62 (Owner-PC) via eth0

Apr  4 07:44:11 server2 dhcpd: DHCPDISCOVER from 00:a0:d1:72:05:62 via
10.20.190.2: load balance to peer dhcp-peer
Apr  4 07:44:11 server2 dhcpd: DHCPDISCOVER from 00:a0:d1:72:05:62 via
10.20.190.2: load balance to peer dhcp-peer
Apr  4 07:44:15 server2 dhcpd: DHCPDISCOVER from 00:a0:d1:72:05:62 via
10.20.190.2
Apr  4 07:44:15 server2 dhcpd: uid lease 10.20.191.186 for client
00:a0:d1:72:05:62 is duplicate on 10.20.190/23
Apr  4 07:44:15 server2 dhcpd: DHCPREQUEST for 10.20.190.163
(10.20.32.35) from 00:a0:d1:72:05:62 via 10.20.190.2: lease owned by peer
Apr  4 07:44:16 server2 dhcpd: DHCPOFFER on 10.20.191.186 to
00:a0:d1:72:05:62 (Owner-PC) via 10.20.190.2
Apr  4 07:44:19 server2 dhcpd: DHCPACK to 10.20.190.163
(00:a0:d1:72:05:62) via eth1
Apr  4 07:45:23 server2 dhcpd: DHCPACK to 10.20.190.163
(00:a0:d1:72:05:62) via eth1
Apr  4 07:47:28 server2 dhcpd: DHCPACK to 10.20.190.163
(00:a0:d1:72:05:62) via eth1
Apr  4 07:50:16 server2 dhcpd: DHCPACK to 10.20.190.163
(00:a0:d1:72:05:62) via eth1


As Timothy said, it does not seem to affect the host, but it makes me
curious.

Maybe someone out there can shed some light?  Thanks!

cv


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