[Bug 1551351] Re: dhclient does not renew leases

[Doug Smythies]

Stefan, I think the answer is yes. Just a few minutes before my lease was going to expire, I did: "sudo dhclient enp4s0"
However, I didn't notice any change in the leases file, so I expected internet it to stop working after the expire time, but it didn't stop working. So I looked at my tcpdump captures and realized  that the lease was granted, it just didn't update the leases file.

I never killed anything first, and dhclient is still running... Oh,
crap, I see I now have a bunch of dhclients running.

doug at DOUG-64:~$ ps aux | grep dhcl
root      1049  0.0  0.0 181364  2808 ?        Ss   Feb29   0:00 /sbin/dhclient -1 -v -pf /run/dhclient.enp4s0.pid -lf /var/lib/dhcp/dhclient.enp4s0.leases -I -df /var/lib/dhcp/dhclient6.enp4s0.leases enp4s0
root      7008  0.0  0.0 181364  2796 ?        Ss   07:34   0:00 dhclient enp4s0
root      7368  0.0  0.0 181364  2744 ?        Ss   08:01   0:00 dhclient enp4s0
root      7616  0.0  0.0 181364  2688 ?        Ss   08:36   0:00 dhclient enp4s0
root      7810  0.0  0.0 181364  2816 ?        Ss   08:36   0:00 dhclient enp4s0

I was just trying to avoid having a gap in internet access. I don't
really want to do the ifdown && ifup method if I can avoid it.

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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)

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