Summary

This chapter introduces Netadmins to IPSec-based VPNs. The initial section discusses the architecture and terminology within the IPSec framework. Successive sections cover the interoperability of Cisco-based VPN devices with Linux- and Windows-based VPN servers.

The chapter helps Netadmins do the following tasks:

• Understand the various components and functions of the IPSec protocol

• Understand IPSec-based VPNs

• Deploy Cisco IOS based VPNs in a mixed environment using a Linux OpenSWAN VPN server

• Deploy Cisco PIX Firewall based VPNs in a mixed environment using a Linux OpenSWAN VPN server

• Deploy Cisco VPN 3000 concentrator based VPNs in a mixed environment using a Linux OpenSWAN VPN server

• Deploy Cisco IOS based VPNs in a mixed environment using MS-Windows IPSec services

• Deploy Cisco PIX Firewall based VPNs in a mixed environment using MS-Windows IPSec services

• Deploy Cisco VPN 3000 concentrator based VPNs in a mixed environment using MS-Windows IPSec services

Table 10-17 lists the tools discussed in this chapter.

Table 10-17. IPSec Resources

Tool	Function	Supported OS	URL/Notes
OpenSWAN	IPSec-based VPN server	Linux	http://www.openswan.org
FreeSWAN	IPSec-based VPN server	Linux	http://www.freeswan.org
Windows IPSec Services	IPSec-based VPN server	Windows 2000/XP/2003	http://www.microsoft.com