Casio ISA550WBUN3K9 manual 283058

VPN	8
Configuring a Site-to-Site VPN

Figure 4 Networking Example that Simulates Two Merging Companies with the Same IP Addressing Scheme

172.16.1.2

Site A

172.16.1.1

Router A

NAT pool 10.5.76.58 172.18.x.x

NAT pool

172.19.x.x 10.5.76.57

ISA500

172.16.1.1

Site B

172.16.1.2

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In this example, when the host 172.16.1.2 at Site A accesses the same IP-addressed host at Site B, it connects to a 172.19.1.2 address rather than to the actual 172.16.1.2 address. When the host at Site B to access Site A, it connects to a 172.18.1.2 address. NAT on Router A translates any 172.16.x.x address to look like the matching 172.18.x.x host entry. NAT on the ISA500 changes 172.16.x.x to look like 172.19.x.x.

NOTE: This configuration only allows the two networks to communicate. It does not allow for Internet connectivity. You need additional paths to the Internet for connectivity to locations other than the two sites; in other words, you need to add another router or firewall on each side, with multiple routes configured on the hosts.

•IKE Policy: Choose the IKE policy used for the IPsec VPN policy. You can click IKE Policy Link to maintain the IKE policies, but save your settings on this page first.

•Transform: Choose the transform set used for the IPsec VPN policy. You can click Transform Link to maintain the transform policies, but save your settings on this page first.

Cisco ISA500 Series Integrated Security Appliances Administration Guide 347