[Dnsmasq-discuss] bad dhcp clients

Bill McCormick wpmccormick at gmail.com
Wed Dec 12 20:33:22 GMT 2012


I have some clients that keep requesting IP address's, while some are 
happy after they are served. Below is a look at the last 100 lines for 
syslog for certain clients. The common thread for the well behaved 
clients is that they all send a client name. Of the mis-behaving 
clients, all save one (EIP1) DO NOT end client names. None of these 
clients are runs an accessible OS  (Linux or Windows); they're all 
proprietary industrial control systems.

Wed Dec 12 14:19:30 CST 2012
root at sam:/home/fiber# tail -n100 /var/log/syslog | grep PLC1
Dec 12 14:16:10 sam dnsmasq-dhcp[830]: DHCPACK(eth1) 172.16.122.20 
00:00:bc:ce:42:c9 PLC1
Dec 12 14:17:05 sam dnsmasq-dhcp[830]: DHCPACK(eth1) 172.16.122.20 
00:00:bc:ce:42:c9 PLC1
Dec 12 14:17:59 sam dnsmasq-dhcp[830]: DHCPACK(eth1) 172.16.122.20 
00:00:bc:ce:42:c9 PLC1
Dec 12 14:18:53 sam dnsmasq-dhcp[830]: DHCPACK(eth1) 172.16.122.20 
00:00:bc:ce:42:c9 PLC1
root at sam:/home/fiber# tail -n100 /var/log/syslog | grep SPIN1
Dec 12 14:16:51 sam dnsmasq-dhcp[830]: DHCPACK(eth1) 172.16.122.201 
00:0c:61:00:ac:83 SPIN1
Dec 12 14:16:54 sam dnsmasq-dhcp[830]: DHCPACK(eth1) 172.16.122.201 
00:0c:61:00:ac:83 SPIN1
Dec 12 14:17:52 sam dnsmasq-dhcp[830]: DHCPACK(eth1) 172.16.122.201 
00:0c:61:00:ac:83 SPIN1
Dec 12 14:17:54 sam dnsmasq-dhcp[830]: DHCPACK(eth1) 172.16.122.201 
00:0c:61:00:ac:83 SPIN1
Dec 12 14:18:52 sam dnsmasq-dhcp[830]: DHCPACK(eth1) 172.16.122.201 
00:0c:61:00:ac:83 SPIN1
Dec 12 14:18:54 sam dnsmasq-dhcp[830]: DHCPACK(eth1) 172.16.122.201 
00:0c:61:00:ac:83 SPIN1
root at sam:/home/fiber# tail -n100 /var/log/syslog | grep SPIN2
Dec 12 14:16:29 sam dnsmasq-dhcp[830]: DHCPACK(eth1) 172.16.122.202 
00:0c:61:00:ac:a3 SPIN2
Dec 12 14:16:54 sam dnsmasq-dhcp[830]: DHCPACK(eth1) 172.16.122.202 
00:0c:61:00:ac:a3 SPIN2
Dec 12 14:17:30 sam dnsmasq-dhcp[830]: DHCPACK(eth1) 172.16.122.202 
00:0c:61:00:ac:a3 SPIN2
Dec 12 14:17:54 sam dnsmasq-dhcp[830]: DHCPACK(eth1) 172.16.122.202 
00:0c:61:00:ac:a3 SPIN2
Dec 12 14:18:32 sam dnsmasq-dhcp[830]: DHCPACK(eth1) 172.16.122.202 
00:0c:61:00:ac:a3 SPIN2
Dec 12 14:18:54 sam dnsmasq-dhcp[830]: DHCPACK(eth1) 172.16.122.202 
00:0c:61:00:ac:a3 SPIN2
Dec 12 14:19:33 sam dnsmasq-dhcp[830]: DHCPACK(eth1) 172.16.122.202 
00:0c:61:00:ac:a3 SPIN2
root at sam:/home/fiber# tail -n100 /var/log/syslog | grep CTC1
root at sam:/home/fiber# tail -n100 /var/log/syslog | grep EIP1
Dec 12 14:17:27 sam dnsmasq-dhcp[830]: DHCPACK(eth1) 172.16.122.215 
00:30:11:07:de:51 EIP1
Dec 12 14:18:29 sam dnsmasq-dhcp[830]: DHCPACK(eth1) 172.16.122.215 
00:30:11:07:de:51 EIP1
Dec 12 14:19:31 sam dnsmasq-dhcp[830]: DHCPACK(eth1) 172.16.122.215 
00:30:11:07:de:51 EIP1
root at sam:/home/fiber# tail -n100 /var/log/syslog | grep HMI1
root at sam:/home/fiber# tail -n100 /var/log/syslog | grep LTX1

... and a local dnsmasq conf file (referenced from /etc/dnsmasq.conf):
domain=hipower.service.fibertech.local

dhcp-option=option:router,172.16.122.254
dhcp-option=option:ntp-server,172.16.122.5

dhcp-range=172.16.122.10,172.16.122.99,24,24h
dhcp-range=172.16.122.200,172.16.122.245,24,24h

dhcp-host=LTX1,172.16.122.11,24h
dhcp-host=HMI,172.16.122.21,24h
dhcp-host=CTC1,172.16.122.31,24h
dhcp-host=EIP1,172.16.122.32,24h
dhcp-host=00:00:bc:ce:42:c9,PLC1,172.16.122.20,24h
dhcp-host=00:0c:61:00:ac:83,SPIN1,172.16.122.201,24h
dhcp-host=00:0c:61:00:ac:a3,SPIN2,172.16.122.202,24h
dhcp-host=00:0c:61:00:b8:3d,ZAXIS1,172.16.122.203,24h
dhcp-host=00:0c:61:00:bb:63,ZAXIS2,172.16.122.204,24h




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