DHCP client keep expired leases if client suspend

Prunk Dump prunkdump at gmail.com
Sat Oct 26 08:18:02 UTC 2019


Hello.

I have a problem with my Debian 10 Buster clients using the last
version of the ISC dhcp client (4.4.1).

Here the problematic scenario :
-> My DHCP server give a 8 hours lease to a client.
-> The client say that it will renew the lease in 4 hours.
-> One hour after the client suspend (not hibernate).
-> The next day (more 24 hour after) a wake the client by Wake-On-Lan.

Instead of request a new lease immediately with DHCPDISCOVER, the
client wait for three hours more before renewing the lease. So the
expired lease it kept during 3 hours. This is like the client use only
the "running elapsed times" and don't notice the time elapsed during
suspend.

But that's not completely true because the client make a DHCPDISCOVER
enstead of a DHCPREQUEST. So the client notice that the lease has
expired. But too late.

I don't know where report the bug :
-> Is this a ISC dhcp client problem ?
-> Or is there a systemd problem that does not signal the suspend to
the DHCP client ?
-> Or a network-manager problem ?

Thanks for any help !

Baptiste.


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