/etc/network/if-pre-up.d and if-post-down.d command not executed after upgrade to Ubuntu 20.04

I just upgraded a droplet from Ubuntu 18.04 to 20.04 via do-release-upgrade.

I have commands /etc/network/if-pre-up.d/iptablesload and /etc/network/if-post-down.d/iptablessave which are intended to save and restore iptables over a reboot. These worked fine on Ubuntu 18.04 and still work fine if run manually, but they don’t run automatically on reboot. I don’t know if any other if-down.d/, if-post-down.d/, if-pre-up.d/ or if-up.d/ commands are run. They may or may not not be.

I expect something is missing as I have no man pages for ‘interfaces’, ‘ifup’ or ‘ifdown’ either.

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With a update I lost connection and after the reboot the network was not working. And via the Droplet -> Networking -> Revovery console:

ifdown eth0
ifup eth0

I had network running:-)

I noticed the some modules for cloud-init where missing.

apt purge cloud-init
apt install cloud-init

Fixed the problem.


Apparently after the upgrade ‘apt autoremove’ removed ‘ifupdown:amd64 0.8.35ubuntu1’

‘apt install ifupdown’ fixed the issue.