cannot renew IPV6 address

Jean-Max Reymond jmreymond at
Thu Jan 26 16:13:40 UTC 2017

Le 26/01/2017 à 17:01, Simon Hobson a écrit :
> Jean-Max Reymond <jmreymond at> wrote:
>> After 12 hours, the interface is down and I cannot obtain a new IPV6 adress.
>> $ /usr/local/sbin/dhclient -cf /etc/dhcp/dhclient6.conf -6 -P -v eno1
>> ...
>> RCV:  | | | X-- Max lifetime 43200.
> OK, your lease is 12 hours, at the end of the lease you lose the address. Are you leaving the dhcp client running ? Is it sending any renewal requests ? Are you running a firewall that could be blocking DHCP6 ?

thanks for your fast answer. dhcp client is always running but I cannot 
ping6 another server.
I have no messages in /var/log/syslog and no firewall.
At boot, IPV6 is OK.
So I suspect this bug
but after updating with dhcpclient 4.3.5, same issue

> The basic troubleshooting at this point is to narrow it down to one of 3 things :
> 1) Your client isn't attempting to renew
> 2) Your client is attempting to renew but the server isn't responding
> 3) Something else - such as server responding but client doesn't accept it
> You probably need to run a packet sniffer on the relevant interface and capture DHCP6 packets. That should answer the questions: Is the client trying to renew ? Is the server replying ?

OK, I suspect answer 1 because I have no traces in /var/log/syslog but 
restarting dhclient give answer 2
I start a sniffer client to capture DHCP6 packets

Jean-Max Reymond
CKR Solutions Open Source

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