Hello,
I'm having this issue (maybe two) which, after digging a bit around I
presume are related to dhclient.
This is what I do to reproduce the issues:
- Boot the system with ethernet cable disconnected
- Wait dhclient to timeout
- Connect the cable
- dhclient keeps sleeping and the interface is still without address
My context:
- Debian Jessie on an ARM system (cubieboard2).
- dhclient 4.3.1
This is the output of dhclient when run by hand:
----------------------------------------------------------------
# dhclient -d -v -pf /run/dhclient.eth0.pid -lf /var/lib \
/dhcp/dhclient.eth0.leases eth0
Internet Systems Consortium DHCP Client 4.3.1
Copyright 2004-2014 Internet Systems Consortium.
All rights reserved.
For info, please visit
https://www.isc.org/software/dhcp/Listening on LPF/eth0/02:14:06:40:c1:2c
Sending on LPF/eth0/02:14:06:40:c1:2c
Sending on Socket/fallback
DHCPREQUEST on eth0 to 255.255.255.255 port 67
DHCPREQUEST on eth0 to 255.255.255.255 port 67
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 6
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 8
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 9
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 8
No DHCPOFFERS received.
Trying recorded lease 192.168.1.157
PING 192.168.1.1 (192.168.1.1) 56(84) bytes of data.
--- 192.168.1.1 ping statistics ---
1 packets transmitted, 0 received, +1 errors, 100% packet loss, time 0ms
bound: renewal in 120825 seconds.
----------------------------------------------------------------
It looks like the IP address is properly taken from a previously
obtained lease, however the address is actually not assigned to the
interface being down:
# ip link show eth0
3: eth0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast
state DOWN mode DEFAULT group default qlen 1000
link/ether 02:14:06:40:c1:2c brd ff:ff:ff:ff:ff:ff
When a cable is connected is appears that dhclient does not notice the
link status change (is it supposed to? I think it should!) and just
keeps the lease for that long time without actually assigning the IP
address to the interface.
The second issue is that the board lacks a RTC chip and always boots
with the real time clock set to 2010/1/1 0:00 UTC thus when calculating
the lease length huge numbers may come out if the old lease has been
obtained while NTP-synced:
------------------------------------
No DHCPOFFERS received.
Trying recorded lease 192.168.1.157
PING 192.168.1.1 (192.168.1.1) 56(84) bytes of data.
--- 192.168.1.1 ping statistics ---
1 packets transmitted, 0 received, +1 errors, 100% packet loss, time 0ms
bound: renewal in 166644509 seconds.
-------------------------------------
What concerns me is that some scenario (for example a power cycle of the
device and its connected switch) may lead to a boot where the IP address
is not properly assigned if not in days/years.
Thank you,
Bye,
--
Daniele Orlandi
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