VPN
Configuring the Cisco IPSec VPN Client
Cisco ISA500 Series Integrated Security Appliance Administrator Guide
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Eliminates the need for end users to purchase and configure external VPN
devices.
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Eliminates the need for end users to install and configure Cisco VPN Client
software on their PCs.
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Offloads the creation and maintenance of the VPN connections from the PC
to the router.
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Reduces interoperability problems between the different PC-based
software VPN clients, external hardware-based VPN solutions, and other
VPN applications.
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Sets up a single IPsec tunnel regardless of the number of multiple subnets
that are supported and the size of the split-include list.
Modes of Operation
The Cisco VPN hardware client supports two operation modes: Client Mode or
Network Extension Mode (NEM). The operation mode determines whether the
inside hosts relative to the Cisco VPN hardware client are accessible from the
corporate network over the tunnel. Specifying a operation mode is mandatory
before making a connection because the Cisco VPN hardware client does not
have a default mode.
All modes of operation also optionally support split tunneling, which allows secure
access to corporate resources through the VPN tunnel while also allowing Internet
access through a connection to an Internet service provider (ISP) or other
service—thereby eliminating the corporate network from the path for web access.
This section includes the following topics:
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Network Extension Mode, page 241
Client Mode
Client mode specifies that NAT or PAT be done so that the PCs and other hosts at
the remote end of the VPN tunnel form a private network that does not use any IP
addresses in the IP address space of the desination server. In Client mode, the
outside interface of the Cisco VPN hardware client can be assigned an IP address
by the remote server.
