In this chapter, we will learn how to use tools to debug and monitor our VPN tunnels. We will also learn how to scan and test the connectivity of a (VPN) server with standard networking tools.
In our typical OpenVPN setup, we have connected two networks (192.168.250.0/24 and 172.16.76.0/24) via two Linux servers that are connected to the Internet via a default gateway. Between the two Linux servers is a tunnel that uses the virtual IPs 10.179.10.1 and 10.179.10.2.
In the connected local networks there are two Linux machines that we will use to test our tunnels (perhaps by conveniently accessing them remotely with Secure Shell). We will now use the tools