Regular DHCP network drop
I get a pretty regular (usually mid/late afternoon) DHCP network drop
which appears to affect me but not other users (Mac/Windows) in the
office.
Configured interface is eth0:
$ /sbin/ifconfig
eth0 Link encap:Ethernet HWaddr f0:de:f1:12:02:18
inet addr:172.16.0.167 Bcast:172.16.0.255 Mask:255.255.255.0
...
About an hour ago I find a logged DHCP request:
Wed Feb 23 16:09:19 PST 2011
Feb 23 15:09:12 localhost dhclient: DHCPREQUEST on eth0 to 172.16.0.6 port 67
Feb 23 15:09:12 localhost dhclient: DHCPACK from 172.16.0.6
Feb 23 15:09:12 localhost dhclient: Invalid domain list.
Feb 23 15:09:12 localhost dhclient: Invalid domain list.
Feb 23 15:09:12 localhost dhclient: Invalid domain list.
Feb 23 15:09:12 localhost dhclient: bound to 172.16.0.167 -- renewal in 10170 seconds.
Feb 23 15:09:12 localhost NetworkManager[2380]: <info> (eth0): DHCPv4 state changed bound -> renew
Feb 23 15:09:12 localhost NetworkManager[2380]: <info> address 172.16.0.167
Feb 23 15:09:12 localhost NetworkManager[2380]: <info> prefix 24 (255.255.255.0)
Feb 23 15:09:12 localhost NetworkManager[2380]: <info> gateway 172.16.0.1
Feb 23 15:09:12 localhost NetworkManager[2380]: <info> nameserver '172.16.0.6'
Feb 23 15:09:12 localhost NetworkManager[2380]: <info> nameserver '172.16.2.17'
'ip' shows link:
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
... but no neighbor:
$ ip neigh show
172.16.0.1 dev eth0 INCOMPLETE
And route shows my gateway but it's unpingable.
$ /sbin/route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
172.16.0.0 0.0.0.0 255.255.255.0 U 1 0 0 eth0
169.254.0.0 0.0.0.0 255.255.0.0 U 1000 0 0 eth0
0.0.0.0 172.16.0.1 0.0.0.0 UG 0 0 0 eth0
$ ping 172.16.0.1
PING 172.16.0.1 (172.16.0.1) 56(84) bytes of data.
From 172.16.0.167 icmp_seq=2 Destination Host Unreachable
From 172.16.0.167 icmp_seq=3 Destination Host Unreachable
^C
--- 172.16.0.1 ping statistics ---
5 packets transmitted, 0 received, +2 errors, 100% packet loss, time 4006ms
pipe 2
The resolution is to run 'ifconfig eth0 down; ifdown eth0; dhclient -v
eth0' as root, but I'd like to know why it's necessary in the first
place.
DHCP server is a box in the office running CentOS. I see the DHCP
requests and lease offers there, no sign of expiry.
Suggestions welcomed.
--
Dr. Ed Morbius, Chief Scientist / |
Robot Wrangler / Staff Psychologist | When you seek unlimited power
Krell Power Systems Unlimited | Go to Krell!
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