Comment 1 for bug 1803203

Hi Andy,

I have another user reporting exactly the same issue and with exactly the same requirement to set the source address for outgoing traffic, so I have set the issue as Confirmed.

I want to discuss the best way to achieve what you want. Do you actually want to be able to set a non-zero lifetime, or do you just want to be able to set the lifetime to zero to disable using that address as a source address?

If you just want to be able to disable an address for use as a source address, that's at least conceptually simple, but I don't have a good way to describe it in the YAML at the moment that doesn't require rewriting large parts of the parser.

If you want to be able to set a non-zero preferred lifetime, I have some follow-up questions:

 - What should the behaviour be when you run netplan apply after the system has booted? Currently it will restart systemd-networkd, which will delete and re-add the address, which will have the effect of resetting the timer.

 - Do you expect something to happen when the preferred lifetime expires? There's no way to describe an action to happen afterwards, so it would be very easy to accidentally specify a configuration that cuts the interface off from IPv6 after some time.

Regards,
Daniel