On Wive-NG router when talking about VPN you have either PPP or WireGuard. As PPP is first listed so I tried it before trying WireGuard. Here are my thoughts. Configuration is pretty simple. In the router menu, go to Services – VPN Server. Then select PPTP protocol. In the Users section create new user with login and password and that’s all from the server side.

From the client side it is also pretty simple. First install pptp-linux:

sudo apt install pptp-linux
cd /etc/ppp/peers
touch PPTP

Next thing is to fill configuration file with settings as follows:

pty "pptp x.x.x.x --nolaunchpppd --debug"
name USERNAME
password PASSWORD
remotename PPTP
require-mppe-128
require-mschap-v2
refuse-eap
refuse-pap
refuse-chap
refuse-mschap
noauth
debug
persist
maxfail 0
defaultroute
replacedefaultroute
usepeerdns

With this configuration it is time to activate connection:

chmod 600 /etc/ppp/peers/PPTP
pon PPTP

To disable connection:

poff PPTP

There is one downside of using it. It create several routes of course but it prevents accessing client from outside, so in case of setting it up on remote host you will instantly loose connection. On a local machine it will not be a problem.