Quote from Gigabit Networks:
when an 'iperf' packet is sent to the VPN server IP address, the packet enters the kernel's 'tun0' device. The packet is then forwarded to the userspace OpenVPN process, where the headers are stripped. The packet is encrypted and signed using OpenSSL calls. The encryption and signing algorithms can be configured using the '--cipher' and '--auth' options.
The resulting packet is then fragmented into pieces according to the '--fragment' and --mssfix' options. Afterwards, the encrypted packet is sent out over the regular network to the OpenVPN server. On the server, the process is reversed. First, the packet is reassembled, then decrypted and finally sent out the 'tun0' interface.
The given example shows the packetflow between two machines.
Let`s say we have routed client -> server -> client
The server has two ports: client -> (eth0 -> server -> eth1) -> client
My question is, how would the packetflow look like internally in the server?