Cisco Systems OL-6426-02 Benutzerhandbuch

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Cisco 1800 Series Integrated Services Routers (Fixed) Software Configuration Guide
OL-6426-02
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Configuring VPNs Using an IPSec Tunnel and 
Generic Routing Encapsulation
The Cisco 1800 series integrated services fixed-configuration routers support the creation of virtual 
private networks (VPNs). 
Cisco routers and other broadband devices provide high-performance connections to the Internet, but 
many applications also require the security of VPN connections which perform a high level of 
authentication and which encrypt the data between two particular endpoints. 
Two types of VPNs are supported—site-to-site and remote access. Site-to-site VPNs are used to connect 
branch offices to corporate offices, for example. Remote access VPNs are used by remote clients to log 
in to a corporate network.
The example in this chapter illustrates the configuration of a site-to-site VPN that uses IPSec and the 
generic routing encapsulation (GRE) protocol to secure the connection between the branch office and 
the corporate network. 
 shows a typical deployment scenario. 
Figure 7-1
Site-to-Site VPN Using an IPSec Tunnel and GRE
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Branch office containing multiple LANs and VLANs
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Fast Ethernet LAN interface—With address 192.165.0.0/16 (also the inside interface for NAT)
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VPN client—Cisco 1800 series integrated services router
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Fast Ethernet or ATM interface—With address 200.1.1.1 (also the outside interface for NAT)
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LAN interface—Connects to the Internet; with outside interface address of 210.110.101.1
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VPN client—Another router, which controls access to the corporate network
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Internet
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