I run a NAT router on Debian 10 which takes only a few seconds to reboot, way less then 120 seconds, more like 3. I'd like to keep established connections so that a reboot of the router does not break natted TCP connections, but I don't have the capacities to run two synching routers. How do I persist the conntrack tables on a single machine?
Turns out, it does not work right now with packaged versions of the conntrack-tools, but it works with the not yet released changes. This commit introduces a save output format which will write the
conntrack command line parameters needed to restore the conntrack tables. With this information it's easy to persist the tables. Unfortunately, it is unreleased. Building the conntrack-tools is easy, but it requires an up-to-date version of libnetfilter-conntrack which then might clash with system utilities that depend on a different version.