I'm following this tutorial. What do the IPs mean after the ifconfig here?dev tun0ifconfig 10.9.8.1 10.9.8.2secret /etc/openvpn/static.keyCan I use external IPs (assuming I'm configuring this on a vps/dedicated server)?
OpenVPN static key ip meaning/order?
networking;openvpn
Those are the IP addresses of the local and remote tunnel endpoints (in that order). They're used for routing (and of course the local one is a local IP address, just like on any other interface).You could use public IPs, but its a waste of IP addresses in most casesyou can use internal (RFC1918) addresses even if you're routing a public subnet over the tunnel.They're both /32's, so they don't need to be on the same subnet. E.g., if you're trying to give a public address to the client, you can have only that one be a public IP.As an example of how they're using in routing, let's say that you have a network like this:10.0.0.0/24 ------ fw1 ------ INET ----- fw2 --- 10.1.0.0/2410.0.1.0/24 -------|200.200.200.0/24 -/You build an OpenVPN tunnel between fw1 and fw2. Let's say you have fw1 as 10.255.255.255.1 and fw2 as 10.255.255.2. On fw1, you'd have ifconfig 10.255.255.1 10.255.255.2 (on fw2, it'd be in the other order). On fw1, you'd have routes like:10.1.0.0/24 via 10.255.255.2 dev tun0and on fw2:10.0.0.0/24 via 10.255.255.1 dev tun010.0.1.0/24 via 10.255.255.1 dev tun0200.200.200.0/24 via 10.255.255.1 dev tun0You can add those routes however you likeby the route option in the OpenVPN config, by hand using ip route add, by using a routing daemon like Quagga, etc.