[Bug 1551351] Re: dhclient does not renew leases

[Stefan Bader]

@Dough, yes, so basically did not renew but obtained a new lease (which
sensibly is the same IP as before). And while the dhcp server still
wonders why a client ask for some IP _again_, it also silently marks the
lease time as extended for another period. And since the old clients do
not die (but play dead), you accumulate a new copy every time you run it
(including the initial one).

@Seth, thanks for the link. Reading through it I think it is not only
potentially but very much the problem we got. The upload of isc-dhcp
that started the breakage was very likely the one "no change rebuild"
that was done after upgrading to bind9(.19).

Sounds like one needs to manually twiddle the build back so isc-dhcp
gets a bind9 lib that has threads and epoll disabled (as a work-around).
Not sure how quickly that can be done. This may still have problems on
terminating the process, so maybe needs adaptation of ifdown hooks as
well. But that needs to be seen. First goal is to get dhclient/-server
back working.

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to isc-dhcp in Ubuntu.
https://bugs.launchpad.net/bugs/1551351

Title:
  dhclient does not renew leases

Status in isc-dhcp package in Ubuntu:
  Confirmed
Status in isc-dhcp source package in Xenial:
  Confirmed

Bug description:
  Release: Xenial

  I think this only recently started after some bind9 updates triggered a rebuild. When booting dhclient gets started and acquires an IP address, but it does seem to lock up somewhere as it does not renew the lease.
  In my environment I set the lease time to 5 minutes, so I notice such things rather soon. I looked on the dhcp server side but saw any further dhcp messages come in from the client side.

  Related bugs:
   * bug 1551415:  systemctl stop networking hang / timeout 

  ProblemType: Bug
  DistroRelease: Ubuntu 16.04
  Package: isc-dhcp-client 4.3.3-5ubuntu8
  ProcVersionSignature: Ubuntu 4.4.0-9.24-generic 4.4.3
  Uname: Linux 4.4.0-9-generic x86_64
  ApportVersion: 2.20-0ubuntu3
  Architecture: amd64
  Date: Mon Feb 29 12:32:52 2016
  DhclientLeases:

  SourcePackage: isc-dhcp
  UpgradeStatus: No upgrade log present (probably fresh install)

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/isc-dhcp/+bug/1551351/+subscriptions