Ubuntu
systemd package

22.04 DHCPv6 IPv6 broken (at least on Oracle OCI)

Bug #2025382 reported by Tim K.
38
This bug affects 7 people
Affects Status Importance Assigned to Milestone
systemd (Ubuntu)
Triaged
Medium
Unassigned
Jammy
Triaged
Medium
Unassigned
Lunar
New
Undecided
Unassigned

Bug Description

Ubuntu 22.04.2 LTS
kernel 5.15.0-1038-oracle
systemd 249.11-0ubuntu3.9

After an update a couple weeks ago, Ubuntu 22.04 can no longer get IPv6 via DHCPv6 systemd-networkd, at least on Oracle OCI, but there are also other similar reports, e.g.

https://ubuntuforums.org/showthread.php?t=2487465&p=14146758

Oracle seems to be aware of the issue but they claim it's a Ubuntu 22.04 bug:

https://community.oracle.com/customerconnect/discussion/687610/oci-ipv6-address-not-assigned-to-oci-ubuntu-instance-by-dhcp

The workaround to assign a static IPv6 is not great when managing multiple cloud instances.

See original description
Tim K. (tkubnt)
description: updated
Revision history for this message
Tim K. (tkubnt) wrote :

Running `sudo dhclient -6 <interface>` appears to work, the problem seems to be with the systemd-networkd DHCPv6 client.

Revision history for this message
Dominic (triatic) wrote :

Oracle seem to have started sending invalid bytes at the end of dhcpv6 packets.

Systemd has just issued a patch to work around this.

Can this patch be backported into Ubuntu 22.04?

https://github.com/systemd/systemd/commit/1d2b93ff89f28b18c222321c8c7bc48be2185375

Revision history for this message
Nick Rosbrook (enr0n) wrote :

This does seem like a reasonable thing to backport, yeah.

The patch does not actually apply to v249.11 cleanly, but from a quick look around this is just because of some re-factoring and moving things around. So it should be simple to adapt the patch for the v249.11 codebase.

I will look into patching and testing this out myself. I don't currently have access to Oracle OCI, however.

Changed in systemd (Ubuntu Jammy):
status: New → Confirmed
status: Confirmed → Triaged
importance: Undecided → Medium
Changed in systemd (Ubuntu):
status: New → Fix Released
status: Fix Released → Triaged
importance: Undecided → Medium
tags: added: systemd-sru-next
Revision history for this message
Nick Rosbrook (enr0n) wrote :

Did Oracle make any changes around this or is it still an issue? I have not had the time to try and test this or access to OCI.

Revision history for this message
Jan De Luyck (jdeluyck) wrote :

As far as I'm aware nothing has changed on OCI.

Revision history for this message
Dominic (triatic) wrote :

Oracle seem to have corrected the DHCPv6 server. When I load up an unmodified stock instance of Ubuntu, I now get an IPv6 address immediately like I did before they broke it.

Revision history for this message
Tim K. (tkubnt) wrote :

Interesting because Oracle claimed that it was Ubuntu/systemd that was broken, not their DHCPv6 server, their argument was that the `dhclient -6` works fine.

Revision history for this message
Dominic (triatic) wrote :

It eventually became apparent that Oracle started appending a null byte to DHCPv6 packets a few weeks ago. `dhclient -6` is more tolerant of malformed DHCPv6 packets than networkd's DHCPv6 client.

Revision history for this message
Jan De Luyck (jdeluyck) wrote :

I just tried rebooting my OCI ubuntu 2204 box. Still no ipv6 address until I run dhclient -6.

Nick Rosbrook (enr0n)
tags: removed: systemd-sru-next
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