losing IPv6 address on time change

Simon Hobson dhcp1 at thehobsons.co.uk
Thu Nov 14 17:13:04 UTC 2013

"Mironov, Ivan" wrote:
system starts with incorrect time (unix epoch beginning, it's expected), dhclient starts and bounds IPv6 address;
correct time is established by NTP server response; 
dhclient initiates DEPREF6/EXPIRE6/BOUND6, which causes losing IPv6 address for a little time;

Well it certainly seems logical. If you think about it, the lease obtained in step 1 would have an end time sometime in 1970. After step 2 the system time would be >> lease expiry time, thus leading to step 3.

It's not exactly ideal though. Ideally a large time change like ought to be propagated to time sensitive processes (such as your DHCP client), though I don't know if there's even a mechanism for it. <sticking plaster mode>Is there any way to modify the system to use a link local address to get an initial time (from a server on the same link) and delay bringing up the full networking ? Or failing that, to delay bringing up any more network dependent services until the time is set and the client has had time to sort itself out ?

More information about the dhcp-users mailing list