Connecting from the University network, I often incur into a very annoying issue, that of blocked ports. I have therefore decided to configure a personal VPN (Virtual Private Network) server where to connect to from university and have true freedom of access to whichever service I would need to use.
The configuration is pretty straight forward, starting by installing the Poptop (pptpd) VPN daemon as follows:
# apt-get install ppp pptpd
To specify the local IP address range the VPN server should assign to the client, edit the file
# nano /etc/pptpd.conf
and add the IP range at the bottom of the file:
xxx is the last byte of the RasPi ip of your choice, and
110-120, for instance, the last byte of the custom range of ip assigned to the clients.
To configure the VPN users, proceed as follows:
# nano /etc/ppp/chap-secrets
and add each user with the syntax:
username * password *
Adapt the line above as needed.
Restart the daemon to apply the changes:
# service pptpd restart
Finally, we need to enable IP forwarding:
# nano /etc/sysctl.conf
by adding or uncommenting:
and apply the changes without the need to reboot the machine:
# sysctl -p
Important note: For the VPN server to work, we need to enable on the router IP protocol 47 (GRE) and forward the TCP port 1723 to the RasPi ip address.