Specifications

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Cisco 1800 Series Integrated Services Routers (Fixed) Software Configuration Guide
OL-6426-02
Chapter 7 Configuring VPNs Using an IPSec Tunnel and Generic Routing Encapsulation
Configure a GRE Tunnel
Apply the Crypto Map to the Physical Interface
The crypto maps must be applied to each interface through which IPSec traffic flows. Applying the
crypto map to the physical interface instructs the router to evaluate all the traffic against the security
associations database. With the default configurations, the router provides secure connectivity by
encrypting the traffic sent between remote sites. However, the public interface still allows the rest of the
traffic to pass and provides connectivity to the Internet.
Perform these steps to apply a crypto map to an interface, beginning in global configuration mode:
Configure a GRE Tunnel
Perform these steps to configure a GRE tunnel, beginning in global configuration mode:
Command or Action Purpose
Step 1
interface type number
Example:
Router(config)# interface fastethernet 0
Router(config-if)#
Enters interface configuration mode for the
interface to which you want to apply the crypto
map.
Step 2
crypto map map-name
Example:
Router(config-if)# crypto map static-map
Router(config-if)#
Applies the crypto map to the interface.
See th e Cisco IOS Security Command Reference
for more detail about this command.
Step 3
exit
Example:
Router(config-if)# exit
Router(config)#
Enters global configuration mode.
Command or Action Purpose
Step 1
interface type number
Example:
Router(config)# interface tunnel 1
Router(config-if)#
Creates a tunnel interface and enters interface
configuration mode.
Step 2
ip address ip-address mask
Example:
Router(config-if)# 10.62.1.193
255.255.255.252
Router(config-if)#
Assigns an address to the tunnel.