client LAN routed over the VPN tunnel to the server

December 24, 2023

Content #

On the server side:

openvpn --ifocnfig 10.200.0.1 10.200.0.2 --dev tun --secret secret.key 0 \
--route 192.168.4.0 255.255.255.0 --daemon --log /var/log/vpn_server.log

On the client side:

openvpn --ifconfig 10.200.0.2 10.200.0.1 --dev tun --secret secret.key 1 \
--remote server.ip --daemon --log /var/log/vpn_client.log

Instead of using the OpenVPn –route statement, we can also use the following command:

[root@server]# ip route add 192.168.4.0/24 via 10.200.0.2

这样配置过后，还必须在客户端做如下配置，才能让OpenVPN server ping通client LAN上的机器。 client LAN side:

IP Forwarding or routing needs to be enabled on the OpenVPN client.
```
net.ipv4.ip_forward=1
```
Make sure that there is a route back to the OpenVPN server on the client LAN. This can be done by adding a route to the LAN geteway, or by adding a static route to each of the machines on the client LAN.
```
ip route add 10.200.0.0/24 via 192.168.4.100
```
192.168.4.100为OpenVPN client在LAN中的IP地址。

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