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Re: dhclient changes IP address



Rainer Dorsch wrote:
> Another non-standard behavior might be that the system (Cubox-i) has no RTC, 
> i.e. when the system boots, it always thinks it is in Jan 1st, 1970.

That is the same as the Raspberry Pi.  On the Pi they use a clever
hack.  At shutdown a file holds the timestamp of the time when the
system shutdown.  On boot the timestamp is used to set the current
time for the system.  That way the time doesn't go all of the way to
1970-01-01 00:00 but only back to the time of the last shutdown.

> Then when NTP eventually updated the time (and even then some hours

That is also the same as the Pi.  During boot when the network is
established NTP will step the clock forward once during boot to get to
the current time.

> later) it request once a new IP address. I have seen that it go in
> the first assignment 192.168.178.87 and then changes to
> 192.168.178.88 and the other way round.

Hmm...  I don't know what would cause that.

> Here are the logs from the client side:
> 
> root@bokocube:/var/log# zgrep "dhclient" syslog.5.gz  syslog.4.gz 
> syslog.5.gz:Jan  1 01:00:07 bokocube dhclient: Listening on 
> LPF/eth0/d0:63:b4:00:32:5c
> syslog.5.gz:Jan  1 01:00:07 bokocube dhclient: Sending on   
> LPF/eth0/d0:63:b4:00:32:5c
> syslog.5.gz:Jan  1 01:00:07 bokocube dhclient: Sending on   Socket/fallback
> syslog.5.gz:Jan  1 01:00:07 bokocube dhclient: DHCPREQUEST on eth0 to 
> 255.255.255.255 port 67
> syslog.5.gz:Jan  1 01:00:10 bokocube NetworkManager[333]: <info> dhclient 
> started with pid 429
> syslog.5.gz:Jan  1 01:00:10 bokocube dhclient: Internet Systems Consortium 
> DHCP Client 4.3.0
> syslog.5.gz:Jan  1 01:00:10 bokocube dhclient: Copyright 2004-2014 Internet 
> Systems Consortium.
> syslog.5.gz:Jan  1 01:00:10 bokocube dhclient: All rights reserved.
> syslog.5.gz:Jan  1 01:00:10 bokocube dhclient: For info, please visit 
> https://www.isc.org/software/dhcp/
> syslog.5.gz:Jan  1 01:00:10 bokocube dhclient: 
> syslog.5.gz:Jan  1 01:00:10 bokocube dhclient: Listening on LPF/eth0/d0:63:b4:00:32:5c
> syslog.5.gz:Jan  1 01:00:10 bokocube dhclient: Sending on LPF/eth0/d0:63:b4:00:32:5c
> syslog.5.gz:Jan  1 01:00:10 bokocube dhclient: Sending on   Socket/fallback
> syslog.5.gz:Jan  1 01:00:10 bokocube dhclient: DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 7
> syslog.5.gz:Jan  1 01:00:11 bokocube dhclient: DHCPREQUEST on eth0 to 255.255.255.255 port 67
> syslog.5.gz:Jan  1 01:00:11 bokocube dhclient: DHCPOFFER from 192.168.178.1
> syslog.5.gz:Jan  1 01:00:11 bokocube dhclient: DHCPACK from 192.168.178.1
> syslog.5.gz:Jan  1 01:00:11 bokocube dhclient: bound to 192.168.178.88 -- renewal in 379228 seconds.
> syslog.5.gz:Jan  1 01:00:11 bokocube dhclient: DHCPREQUEST on eth0 to 255.255.255.255 port 67
> syslog.5.gz:Jan  1 01:00:11 bokocube dhclient: DHCPACK from 192.168.178.1
> syslog.5.gz:Jan  1 01:00:11 bokocube dhclient: bound to 192.168.178.88 -- renewal in 418840 seconds.
> syslog.4.gz:Jun 23 03:45:01 bokocube dhclient: DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 7
> syslog.4.gz:Jun 23 03:45:01 bokocube dhclient: DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 5
> syslog.4.gz:Jun 23 03:45:02 bokocube dhclient: DHCPREQUEST on eth0 to 255.255.255.255 port 67
> syslog.4.gz:Jun 23 03:45:02 bokocube dhclient: DHCPOFFER from 192.168.178.1
> syslog.4.gz:Jun 23 03:45:02 bokocube dhclient: DHCPACK from 192.168.178.1
> syslog.4.gz:Jun 23 03:45:02 bokocube dhclient: bound to 192.168.178.88 -- renewal in 415195 seconds.
> syslog.4.gz:Jun 23 03:45:02 bokocube dhclient: DHCPREQUEST on eth0 to 255.255.255.255 port 67
> syslog.4.gz:Jun 23 03:45:02 bokocube dhclient: DHCPOFFER from 192.168.178.1
> syslog.4.gz:Jun 23 03:45:03 bokocube dhclient: DHCPACK from 192.168.178.1
> syslog.4.gz:Jun 23 03:45:03 bokocube dhclient: bound to 192.168.178.87 -- renewal in 415153 seconds.
> root@bokocube:/var/log# 

I don't know.  It doesn't seem like it should be doing that.  Where
"that" I define to be that the dhcp server offers a different address
each time.

This feels to me to be more likely to be a dhcp server problem.

Can you isolate the problem to either the client or the server by
splitting them?  For example, does another dhcp client also change
addresses?  Does the client work okay on a different dhcp server?  Not
sure that is practical for you to test.

Bob

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