6 Configuring Vpn Server; Overview - Novell LINUX ENTERPRISE DESKTOP 11 - SECURITY GUIDE 17-03-2009 Manual

Configuring VPN Server
Internet connections these days are cheap and available almost everywhere, although
insecure. VPN, the Virtual Private Network, is a secure network within a second, insecure
network such as the Internet or WLAN. It can be implemented in different ways and
has several meanings. In this chapter we focus on VPNs to link branch offices via secure
wide area networks (WANs).

16.1 Overview

This section gives you a brief overview of some scenarios which are possible with VPN
and some relevant terminology.
16.1.1 Scenarios with VPN
There are many packages (and even more combinations) that enable the setting up and
building of a VPN connection. This chapter focuses on OpenVPN. In comparison to
other VPN software, OpenVPN can be operated in two modes:
Routed VPN
Routing is easier to set up. It is more efficient and scales better than bridged VPN.
Futhermore it allows the user to tune MTU (Maximum Transfer Unit) to raise effi-
ciency. However, in a hetergeneous environment NetBIOS broadcasts do not work
if you do not have a Samba server on the gateway. If you need IPv6 each tun drivers
on both ends must support this protocol explicitly.
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