I have a VPN server handling various clients; some with ipv4 only, some with ipv4 and ipv6, and some that will be ipv6 only. Some of these clients are roaming, so ideally they should connect to ipv6 if it's available, and fall back to ipv4 if it isn't.
In my current setup, OpenVPN listens to ipv4 and ipv6:
proto udp proto udp6 dev tun
My first question is here: while this seems to work, is it safe and correct to have both proto in one config file?
My clients have two remote instances in the config:
remote vpn.domain.tld port udp6 remote vpn.domain.tld port udp
My question here, as well, as this seems to work (trying udp6 first, if that fails will fallback to udp), is this a good way to do this?