Pros and cons of the key mode
The main use case for using pre-shared key mode is to connect two remote networks, for example, a main office and a remote office of a small company. As soon as more than three users or endpoints are required, it is far easier to use client/server mode, as described in Chapter 4, Client/Server Mode with tun Devices. An example of how to connect three sites together using pre-shared keys is given later in this chapter, and it will become clear why pre-shared key mode does not scale well beyond three sites or users.
The main advantages of using pre-shared key mode are as follows:
It is very easy to set up
There is no need for public key infrastructure (PKI) or X.509 certificates
Can run on limited hardware, such as Linux-based switches or routers
The disadvantages of using pre-shared key mode are:
As the name point-to-point indicates, only two endpoints can be used by a single connection. Therefore, this mode does not scale well.
Some GUI wrappers for OpenVPN (for example...
