networkd does not complete interface configuration if Link MTUBytes is set

Bug #1852754 reported by Dan Streetman
This bug affects 1 person
Affects Status Importance Assigned to Milestone
Fix Released
systemd (Ubuntu)
Dan Streetman

Bug Description


interfaces configured with .network file [Link] section specifying MTUBytes will not be successfully brought up.

[test case]

configure interface e.g.




start/restart networkd, the interface will never reach 'routable' stage and will not get an IPv4 address.

[regression potential]

any regressions would likely occur during networkd configuration/startup/restart, and would likely cause failure to successfully setup the interface.

[other info]

this is a regression-proposed caused by incomplete backport for bug 1850704

Dan Streetman (ddstreet)
Changed in systemd (Ubuntu):
status: New → Fix Released
Changed in systemd (Ubuntu Bionic):
status: New → In Progress
importance: Undecided → Critical
assignee: nobody → Dan Streetman (ddstreet)
tags: added: bionic ddstreet regression-proposed systemd
Changed in systemd:
status: Unknown → Fix Released
Revision history for this message
Steve Langasek (vorlon) wrote : Please test proposed package

Hello Dan, or anyone else affected,

Accepted systemd into bionic-proposed. The package will build now and be available at in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested and change the tag from verification-needed-bionic to verification-done-bionic. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-bionic. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

description: updated
Changed in systemd (Ubuntu Bionic):
status: In Progress → Fix Committed
tags: added: verification-needed verification-needed-bionic
Revision history for this message
Ubuntu SRU Bot (ubuntu-sru-bot) wrote : Autopkgtest regression report (systemd/237-3ubuntu10.33)

All autopkgtests for the newly accepted systemd (237-3ubuntu10.33) for bionic have finished running.
The following regressions have been reported in tests triggered by the package:

gvfs/1.36.1-0ubuntu1.3.3 (ppc64el, amd64)
dovecot/1: (armhf)
umockdev/0.11.1-1 (ppc64el)

Please visit the excuses page listed below and investigate the failures, proceeding afterwards as per the StableReleaseUpdates policy regarding autopkgtest regressions [1].


Thank you!

Revision history for this message
Dan Streetman (ddstreet) wrote :

ubuntu@lp1850704-b:~$ cat /etc/systemd/network/



ubuntu@lp1850704-b:~$ dpkg -l systemd|grep ii
ii systemd 237-3ubuntu10.33 amd64 system and service manager
ubuntu@lp1850704-b:~$ sudo systemctl restart systemd-networkd
ubuntu@lp1850704-b:~$ ip a show dev ens3
2: ens3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 6666 qdisc fq_codel state UP group default qlen 1000
    link/ether 52:54:00:86:c7:44 brd ff:ff:ff:ff:ff:ff
    inet brd scope global dynamic ens3
       valid_lft 3596sec preferred_lft 3596sec
    inet6 fe80::5054:ff:fe86:c744/64 scope link
       valid_lft forever preferred_lft forever

ubuntu@lp1850704-b:~$ networkctl | grep ens3
  2 ens3 ether routable configured

tags: added: verification-done verification-done-bionic
removed: verification-needed verification-needed-bionic
Revision history for this message
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package systemd - 237-3ubuntu10.33

systemd (237-3ubuntu10.33) bionic; urgency=medium

  * d/p/lp1852754/0001-network-do-not-re-set-MTU-when-current-and-requested.patch,
    - Complete link setup after setting mtu (LP: #1852754)

systemd (237-3ubuntu10.32) bionic; urgency=medium

  [ Victor Tapia ]
  * d/p/resolved_disable-connection-downgrade-when-DNSSEC-yes.patch
    Fix regression introduced by
    resolved-Mitigate-DVE-2018-0001-by-retrying-NXDOMAIN-with.patch when
    DNSSEC=yes (LP: #1796501)

  [ Dan Streetman ]
  * d/p/fix-typo-lp1668771-resolved-switch-cache-option-to-a-tri-state-option-s.patch:
    - Fix typo in previous patch
  * d/p/lp1840640-shared-seccomp-add-sync_file_range2.patch:
    - allow sync_file_range2 in nspawn container
      (LP: #1840640)
  * d/p/lp1783994-dissect-Don-t-count-RPMB-and-boot-partitions-8609.patch:
    - avoid systemd-gpt-auto-generator failure if mmc dev present
      (LP: #1783994)
  * d/p/lp1832672-resolved-rework-parsing-of-etc-hosts.patch:
    - do not fail entire file on error when parsing /etc/hosts
    - parse # char anywhere in line as start of comment
      (LP: #1832672)
  * d/p/lp1843381-dell_passthrough_skip_rename_retry.patch,
    - fix rename delay for systems using "Dell MAC passthrough"
      (LP: #1843381)
  * d/p/lp1849733/0001-resolved-longlived-TCP-connections.patch,
    - add TCP pipelining to handle getaddrinfo() fallback to TCP
    - ignore EDNS0 payload limit when responding over TCP (LP: #1849733)
  * d/p/lp1849658-resolved-set-stream-type-during-DnsStream-creation.patch:
    - Fix bug in refcounting TCP stream types (LP: #1849658)
  * d/p/lp1850704/0001-networkd-Unify-set-MTU.patch,
    - Fix setting mtu if interface already up (LP: #1850704)
  * d/extra/dhclient-enter-resolved-hook:
    - only restart resolved if dhclient conf changed (LP: #1805183)

 -- Dan Streetman <email address hidden> Fri, 15 Nov 2019 10:01:16 -0500

Changed in systemd (Ubuntu Bionic):
status: Fix Committed → Fix Released
Revision history for this message
Steve Langasek (vorlon) wrote : Update Released

The verification of the Stable Release Update for systemd has completed successfully and the package is now being released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.

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