[c-nsp] Cisco router randomly not serving DHCP responses

[Ali Jawad]

Hi
I got a Cisco router, it is also the DHCP server of my network the detail
are below.

For some reason the server randomly stops serving IPs to workstations, even
a repair conection does not work. Some computers have a valid IP but it does
not get renewed.


Router#show version
Cisco IOS Software, 2800 Software (C2800NM-ADVIPSERVICESK9-M), Version
12.4(17b)
, RELEASE SOFTWARE (fc2)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2008 by Cisco Systems, Inc.
Compiled Tue 26-Feb-08 01:46 by prod_rel_team

ROM: System Bootstrap, Version 12.4(13r)T, RELEASE SOFTWARE (fc1)

I did enable debug and I got :

Adding to the above I got the following debug info...as you can see below
the mac address 0016.d490.8e9a is trying to get an IP but it is getting the
answer..DHCPD: Allocate an address without class information while
0100.40f4.9689 got 192.168.0.204



Router#
*Apr 16 14:36:43.375: DHCPD: DHCPDISCOVER received from client
0016.d490.8e9a on
interface FastEthernet0/1.
*Apr 16 14:36:43.375: DHCPD: Allocate an address without class information
(192.
168.0.0)
*Apr 16 14:36:43.647: %HA_EM-6-LOG: CLIAccounting: terminal monitor

*Apr 16 14:37:00.535: DHCPD: DHCPDISCOVER received from client
0016.d490.8e9a on
interface FastEthernet0/1.
*Apr 16 14:37:00.535: DHCPD: Allocate an address without class information
(192.
168.0.0)
*Apr 16 14:37:05.375: DHCPD: DHCPDISCOVER received from client
0016.d490.8e9a on
interface FastEthernet0/1.
*Apr 16 14:37:05.379: DHCPD: Allocate an address without class information
(192.
168.0.0)
*Apr 16 14:37:16.375: DHCPD: DHCPDISCOVER received from client
0016.d490.8e9a on
interface FastEthernet0/1.
*Apr 16 14:37:16.375: DHCPD: Allocate an address without class information
(192.
168.0.0)
*Apr 16 14:37:29.375: DHCPD: DHCPDISCOVER received from client
0016.d490.8e9a on
interface FastEthernet0/1.
*Apr 16 14:37:29.379: DHCPD: Allocate an address without class information
(192.
168.0.0)
*Apr 16 14:37:42.375: DHCPD: DHCPDISCOVER received from client
0016.d490.8e9a on
interface FastEthernet0/1.
*Apr 16 14:37:42.375: DHCPD: Allocate an address without class information
(192.
168.0.0)
*Apr 16 14:37:43.551: DHCPD: DHCPINFORM received from client
0100.40f4.9689.ec (
192.168.0.204).
*Apr 16 14:37:43.551: DHCPD: Sending DHCPACK to client 0100.40f4.9689.ec(192.16
8.0.204).
*Apr 16 14:37:43.551: DHCPD: unicasting BOOTREPLY to client 0040.f496.89ec
(192.
168.0.204).
*Apr 16 14:37:46.555: DHCPD: DHCPINFORM received from client
0100.40f4.9689.ec (
192.168.0.204).
*Apr 16 14:37:46.555: DHCPD: Sending DHCPACK to client 0100.40f4.9689.ec(192.16
8.0.204).
*Apr 16 14:37:46.555: DHCPD: unicasting BOOTREPLY to client 0040.f496.89ec
(192.
168.0.204).
*Apr 16 14:38:00.371: DHCPD: DHCPDISCOVER received from client
0016.d490.8e9a on
interface FastEthernet0/1.
*Apr 16 14:38:00.371: DHCPD: Allocate an address without class information
(192.
168.0.0)
*Apr 16 14:38:07.115: DHCPD: DHCPINFORM received from client
0100.1676.6d3b.5e (
192.168.0.182).
*Apr 16 14:38:07.115: DHCPD: Sending DHCPACK to client 0100.1676.6d3b.5e
(192.16
8.0.182).
*Apr 16 14:38:07.115: DHCPD: unicasting BOOTREPLY to client 0016.766d.3b5e
(192.
168.0.182).
*Apr 16 14:38:10.115: DHCPD: DHCPINFORM received from client
0100.1676.6d3b.5e (
192.168.0.182).
*Apr 16 14:38:10.115: DHCPD: Sending DHCPACK to client 0100.1676.6d3b.5e
(192.16
8.0.182).
*Apr 16 14:38:10.115: DHCPD: unicasting BOOTREPLY to client 0016.766d.3b5e
(192.
168.0.182).


Please advice. The pool is:

#show ip dhcp pool

Pool centrale :
Utilization mark (high/low) : 100 / 0
Subnet size (first/next) : 0 / 0
Total addresses : 254
Leased addresses : 143
Pending event : none
1 subnet is currently in the pool :
Current index IP address range Leased addr
0.0.0.0 192.168.0.1 - 192.168.0.254 143