User Manual

Chapter 9. Advanced Use Cases for Access Server
build-dh
The output is as follows:
ai:easy-rsa # ./build-dh
Generating DH parameters, 1024 bit long safe prime, generator 2
This is going to take a long time
.................+...........................................
...................+.............+.................+.........
......................................
Now you can find the generated keys and certificates in the keys subdirectory. The final step in
the key generation process is to copy all files to the machines which need them, taking care to
copy secret files (server.key and client.key) over a secure channel.
9.4.4. Creating Configuration Files
Both the server and client devices must have certain configuration files for OpenVPN to deter-
mine, for example, which IP addresses to use. In this chapter, we will create a basic configuration
file for OpenVPN server and client. We’ll make the PC as server and Access Server as the client.
An example configuration files can be found here: http://openvpn.net/howto.html#examples.
In our example, we use most of the setting described in these files.
Note: The configuration files can be named, for example, server.conf and client.conf in a Linux
system. On Windows they would be named server.ovpn and client.ovpn, where the file extension
is different.
9.4.4.1. Server Configuration File
There are lots of configuration options that can be used with OpenVPN, but this guide only
covers the basic approach to set up a working VPN with minimal effort. The lines needed in the
server configuration file are listed below. After each line, an explanation follows, see
Figure 9-2:
port 1194
• Determines the TCP or UDP port that OpenVPN should listen to. For multiple OpenVPN
instances on the same machine, you’ll need to use a different port for each one. Make sure
your firewall allows traffic through these ports.
proto udp
• Determines whether to use TCP or UDP. We have chosen UDP in our application.
dev tun
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