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The IP address 192.168.1.254 will be assigned to the router located in the branch office. Please make sure this IP is not
used in the head office LAN.
Configuring PPTP VPN in the Branch Office
The IP address 69.1.121.33 is the Public IP address of the router located in head office. If you registered the DDNS
(please refer to the DDNS section of this manual), you can also use the domain name instead of the IP address to
reach the router.
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IPsec is a near-ubiquitous VPN security standard, designed for use with TCP/IP networks. It works at the packet level,
and authenticates and encrypts all packets traveling over the VPN Tunnel. Thus, it does not matter what applications
are used on your PC. Any application can use the VPN like any other network connection.
IPsec VPNs exchange information through logical connections called SAs (Security Associations). An SA is simply a
definition of the protocols, algorithms and keys used between the two VPN devices (endpoints)
There are two security modes possible with IPsec:
Transport Mode
– the payload (data) part of the packet is encapsulated through encryption but the IP header remains
in the clear (unchanged)
Tunnel Mode
– everything is encapsulated including the original IP header, and a new IP header is generated. Only the
new header in the clear (i.e. not protected). This system provides enhanced security.
