Concentrator Site-to-Site Connections

Chapters 7 and 8 focused on using the concentrator to terminate remote access sessions: IPsec, PPTP, L2TP/IPsec, and WebVPN. Most people assume that the concentrator's primary purpose is for remote access connectivity; however, you can also use the concentrator to set up site-to-site connections. With Cisco concentrators, site-to-site sessions commonly are referred to as LAN-to-LAN (L2L) connections. Because Cisco concentrators are fully compliant with IPsec, it is easy to use a concentrator to terminate L2L sessions with other VPN gateway devices such as Cisco routers, PIX and ASA security appliances, other VPN 3000 concentrators, and other vendors' VPN gateway products.

This chapter will focus on using a VPN 3000 concentrator to terminate L2L sessions by covering the following items:

• L2L Connectivity Example
• ISAKMP/IKE Phase 1 Preparation
• Adding Site-to-Site Connections
• Address Translation and L2L Connections