networkd doesn't re-enable ipv6 unless mtu is set
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
systemd (Ubuntu) |
Fix Released
|
Undecided
|
Unassigned | ||
Bionic |
Fix Released
|
Medium
|
Dan Streetman | ||
Disco |
Won't Fix
|
Undecided
|
Unassigned | ||
Eoan |
Fix Released
|
Medium
|
Dan Streetman |
Bug Description
[impact]
if the 'disable_ipv6' procfs setting is disabled, and networkd is configured with ipv6 networking, networkd will not enable ipv6 via the procfs setting unless the interface mtu is also set to a custom value, that doesn't match the current interface mtu.
[test case]
create networkd config similar to:
[Match]
MACAddress=
Name=ens3
[Network]
DHCP=ipv4
LinkLocalAddres
Address=
manually disable ipv6 for the interface:
ubuntu@
1
the interface should not contain any ipv6 addresses:
ubuntu@
ubuntu@
restart networkd; it should enable ipv6 as ipv6 addresses are configured, but it does not:
ubuntu@
ubuntu@
ubuntu@
Note that with the mtu set, it will successfully re-enable ipv6; modify the networkd config to set the mtu by adding this:
[Link]
MTUBytes=1400
(be sure to set the MTU config to something other than its current mtu)
verify ipv6 is still disabled and has no addresses, then restart and check again:
ubuntu@
1
ubuntu@
ubuntu@
ubuntu@
0
ubuntu@
2: ens3: <BROADCAST,
inet6 2001:db8::100/64 scope global
valid_lft forever preferred_lft forever
inet6 fe80::5054:
valid_lft forever preferred_lft forever
That should be the behavior even if MTUBytes is not set.
[regression potential]
as this adjusts when the procfs 'disable_ipv6' setting is changed, the regression potential could cause failure to properly set/create ipv6 addresses, or to leave ipv6 disabled entirely.
[scope]
This is needed in Bionic and Eoan.
the commit to fix this is 482efedc081b0c4
Ignoring Disco, as it is EOL next week.
This problem was introduced by commit 44b598a1c9d11c2
[other info]
for Eoan, this bug has always existed since release, but for Bionic, this is a regression introduced by bug 1850704. However, manual disabling of ipv6 is very unusual, so this bug is unlikely to have an impact to many systems.
Changed in systemd (Ubuntu Disco): | |
status: | New → Won't Fix |
Changed in systemd (Ubuntu Eoan): | |
status: | New → In Progress |
Changed in systemd (Ubuntu Bionic): | |
status: | New → In Progress |
Changed in systemd (Ubuntu): | |
status: | New → Fix Released |
Changed in systemd (Ubuntu Eoan): | |
importance: | Undecided → Medium |
Changed in systemd (Ubuntu Bionic): | |
importance: | Undecided → Medium |
Changed in systemd (Ubuntu Eoan): | |
assignee: | nobody → Dan Streetman (ddstreet) |
Changed in systemd (Ubuntu Bionic): | |
assignee: | nobody → Dan Streetman (ddstreet) |
description: | updated |
description: | updated |
description: | updated |
Changed in systemd (Ubuntu Bionic): | |
status: | Fix Committed → In Progress |
description: | updated |
Hello Dan, or anyone else affected,
Accepted systemd into bionic-proposed. The package will build now and be available at https:/ /launchpad. net/ubuntu/ +source/ systemd/ 237-3ubuntu10. 34 in a few hours, and then in the -proposed repository.
Please help us by testing this new package. See https:/ /wiki.ubuntu. com/Testing/ EnableProposed 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 https:/ /wiki.ubuntu. com/QATeam/ PerformingSRUVe rification . 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.