2

I'm running Ubuntu 16.04.3 LTS and am having a strange problem with dhcp leases not renewing on one interface. The machine has one physical interface and two VLANs; ens3, ens3.1001 and ens3.2002.

The problem occurs when the dhcp lease on ens3 expires, it is not renewed by dhclient. The other two interfaces work fine, their leases are renewed. I've checked dhclient.conf, /etc/network/interfaces, etc, and they are configured the same, so I would think they should behave the same. The only difference I've noticed is in syslog where apparmor logs an audit for dhclient when the lease for ens3 is acquired. It's not clear to me what apparmor is doing, but the lease is acquired, just never renewed. Syslog output is shown below.

I’ve tried running dhclient -v ens3 and the lease is NOT renewed. Toggling the interface up/down does renew it (but this isn’t acceptable since the DNS entry for the interface is removed when the lease expires)

Any insights are greatly appreciated.

/etc/dhcp/dhclient.conf is stock, no changes. Not reproducing it here because it rather long.

Output of ps aux | grep dhcp shows dhclient running on the two VLANs but not the physical interface:

root      1148  0.0  0.0  16128  2960 ?        Ss   Aug30   0:00 /sbin/dhclient -1 -v -pf /run/dhclient.ens3.1001.pid -lf /var/lib/dhcp/dhclient.ens3.1001.leases -I -df /var/lib/dhcp/dhclient6.ens3.1001.leases ens3.1001
root      1232  0.0  0.0  16128  2996 ?        Ss   Aug30   0:00 /sbin/dhclient -1 -v -pf /run/dhclient.ens3.2002.pid -lf /var/lib/dhcp/dhclient.ens3.2002.leases -I -df /var/lib/dhcp/dhclient6.ens3.2002.leases ens3.2002

Partial output fromgrep dhclient /var/log/syslog. The repeating dhcp request and ack for ens3.1001 and 2002 continue for days.

Aug 29 20:54:02 accra dhclient[661]: Internet Systems Consortium DHCP Client 4.3.3
Aug 29 20:54:02 accra dhclient[661]: Copyright 2004-2015 Internet Systems Consortium.
Aug 29 20:54:02 accra dhclient[661]: All rights reserved.
Aug 29 20:54:02 accra dhclient[661]: For info, please visit https://www.isc.org/software/dhcp/
Aug 29 20:54:02 accra dhclient[661]:
Aug 29 20:54:02 accra dhclient[661]: Listening on LPF/ens3/02:03:80:7c:7b:27
Aug 29 20:54:02 accra dhclient[661]: Sending on   LPF/ens3/02:03:80:7c:7b:27
Aug 29 20:54:02 accra dhclient[661]: Sending on   Socket/fallback
Aug 29 20:54:02 accra dhclient[661]: DHCPDISCOVER on ens3 to 255.255.255.255 port 67 interval 3 (xid=0x8e8dd83e)
Aug 29 20:54:02 accra kernel: [    5.253146] audit: type=1400 audit(1504054442.216:2): apparmor="STATUS" operation="profile_load" profile="unconfined" name="/sbin/dhclient" pid=749 comm="apparmor_parser"
Aug 29 20:54:02 accra kernel: [    5.253175] audit: type=1400 audit(1504054442.216:5): apparmor="STATUS" operation="profile_load" profile="unconfined" name="/usr/lib/connman/scripts/dhclient-script" pid=749 comm="apparmor_parser"
Aug 29 20:54:03 accra dhclient[661]: DHCPREQUEST of 192.168.1.171 on ens3 to 255.255.255.255 port 67 (xid=0x3ed88d8e)
Aug 29 20:54:03 accra dhclient[661]: DHCPOFFER of 192.168.1.171 from 192.168.1.8
Aug 29 20:54:04 accra dhclient[661]: DHCPACK of 192.168.1.171 from 192.168.1.8
Aug 29 20:54:05 accra dhclient[661]: bound to 192.168.1.171 -- renewal in 36065 seconds.
Aug 29 20:54:06 accra dhclient[1062]: Internet Systems Consortium DHCP Client 4.3.3
Aug 29 20:54:06 accra dhclient[1062]: Copyright 2004-2015 Internet Systems Consortium.
Aug 29 20:54:06 accra dhclient[1062]: All rights reserved.
Aug 29 20:54:06 accra dhclient[1062]: For info, please visit https://www.isc.org/software/dhcp/
Aug 29 20:54:06 accra dhclient[1062]:
Aug 29 20:54:06 accra dhclient[1062]: Listening on LPF/ens3.1001/02:03:80:7c:7b:27
Aug 29 20:54:06 accra dhclient[1062]: Sending on   LPF/ens3.1001/02:03:80:7c:7b:27
Aug 29 20:54:06 accra dhclient[1062]: Sending on   Socket/fallback
Aug 29 20:54:06 accra dhclient[1062]: DHCPDISCOVER on ens3.1001 to 255.255.255.255 port 67 interval 3 (xid=0xe4320951)
Aug 29 20:54:07 accra dhclient[1062]: DHCPREQUEST of 10.10.0.100 on ens3.1001 to 255.255.255.255 port 67 (xid=0x510932e4)
Aug 29 20:54:07 accra dhclient[1062]: DHCPOFFER of 10.10.0.100 from 10.10.0.8
Aug 29 20:54:07 accra dhclient[1062]: DHCPACK of 10.10.0.100 from 10.10.0.8
Aug 29 20:54:07 accra dhclient[1062]: bound to 10.10.0.100 -- renewal in 1612 seconds.
Aug 29 20:54:07 accra dhclient[1179]: Internet Systems Consortium DHCP Client 4.3.3
Aug 29 20:54:07 accra dhclient[1179]: Copyright 2004-2015 Internet Systems Consortium.
Aug 29 20:54:07 accra dhclient[1179]: All rights reserved.
Aug 29 20:54:07 accra dhclient[1179]: For info, please visit https://www.isc.org/software/dhcp/
Aug 29 20:54:07 accra dhclient[1179]:
Aug 29 20:54:07 accra dhclient[1179]: Listening on LPF/ens3.2002/02:03:80:7c:7b:27
Aug 29 20:54:07 accra dhclient[1179]: Sending on   LPF/ens3.2002/02:03:80:7c:7b:27
Aug 29 20:54:07 accra dhclient[1179]: Sending on   Socket/fallback
Aug 29 20:54:07 accra dhclient[1179]: DHCPDISCOVER on ens3.2002 to 255.255.255.255 port 67 interval 3 (xid=0xd72cc676)
Aug 29 20:54:08 accra dhclient[1179]: DHCPREQUEST of 10.20.0.100 on ens3.2002 to 255.255.255.255 port 67 (xid=0x76c62cd7)
Aug 29 20:54:08 accra dhclient[1179]: DHCPOFFER of 10.20.0.100 from 10.20.0.8
Aug 29 20:54:08 accra dhclient[1179]: DHCPACK of 10.20.0.100 from 10.20.0.8
Aug 29 20:54:08 accra dhclient[1179]: bound to 10.20.0.100 -- renewal in 1735 seconds.
Aug 29 21:20:59 accra dhclient[1135]: DHCPREQUEST of 10.10.0.100 on ens3.1001 to 10.10.0.8 port 67 (xid=0x510932e4)
Aug 29 21:20:59 accra dhclient[1135]: DHCPACK of 10.10.0.100 from 10.10.0.8
Aug 29 21:20:59 accra dhclient[1135]: bound to 10.10.0.100 -- renewal in 1405 seconds.
Aug 29 21:23:03 accra dhclient[1219]: DHCPREQUEST of 10.20.0.100 on ens3.2002 to 10.20.0.8 port 67 (xid=0x76c62cd7)
Aug 29 21:23:03 accra dhclient[1219]: DHCPACK of 10.20.0.100 from 10.20.0.8
Aug 29 21:23:03 accra dhclient[1219]: bound to 10.20.0.100 -- renewal in 1763 seconds.
Aug 29 21:44:24 accra dhclient[1135]: DHCPREQUEST of 10.10.0.100 on ens3.1001 to 10.10.0.8 port 67 (xid=0x510932e4)

Thoughts?

Thank you, Jack

Your Answer

By clicking "Post Your Answer", you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.