I've entirely configured (remotely) a Debian GNU/Linux dedicated server hosted in a professional capacity and I've got a network routing question (which AFAICT precisely fits the FAQ of serverfault).
That dedicated server has a static IPv4 IP and a very simple route:
route -n Table de routage IP du noyau Destination Passerelle Genmask Indic Metric Ref Use Iface 94.xx.yy.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0 0.0.0.0 94.xx.yy.254 0.0.0.0 UG 0 0 0 eth0
I've only one static IP and there are a lot of other dedicated servers on the same subnet which I cannot mess with.
That server is hosting/serving our company's main webapp (Apache+Tomcat) and is running Squid as well. I did all the configuration myself. Once the budget allows it I'll move Squid to another server.
For now I'd like to add OpenVPN to that server (preferably using tun, not tap) and I want to know what needs to be done to be sure that my interfaces won't "clash" with the other dedicated servers.
I don't understand how the setup should be done and I'm confused as to what the route shall end up looking like.
In order to help me understand the "big picture", could someone give a precise example of:
- local IP address of an OpenVPN client
- gateway IP that that OpenVPN client shall be using
- the route output of the OpenVPN server
Basically I'm a bit lost and before starting I'd like to understand how the routing is done on the OpenVPN server.
As far as I understand it the OpenVPN clients shall be on the same network that the OpenVPN server (using, say, a 10.0.0.0/8 network) but I'm hitting a mental roadblock trying to figure out how the clients are going to use the 'tun' interface to then end up using the 94.xx.yy.254 gateway.