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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