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Network configuration
Network address translation (NAT)
About PPTP client routes (Internet port)
If you disabled the Auto-route discovery option (VPN > PPTP client), or if you need to
access IP addresses that are not part of the specified domain, you must define the
appropriate persistent routes.
About PPTP server routes (Internet port)
Activation of the route can be triggered by a specific username. When a user establishes a
connection with the service controller PPTP server, its username is checked against the
persistent routes list and if a match is found, the route is enabled.
Network address translation (NAT)
Network address translation is an address mapping service that enables one set of IP
addresses to be used on an internal network, and a second set to be used on an external
network. NAT handles the mapping between the two sets of addresses.
Generally NAT is used to map all addresses on an internal network to a single address for use
on an external network like the Internet. The main benefits are that NAT:
Enables several devices to share a single connection
Effectively hides from the outside network the IP addresses of all devices on the internal
network.
This is illustrated as follows:
Internet
Web
server
Web Page
Web Page
192.168.1.2
NAT
192.168.1.3
ISP
addressed to
192.168.1.2
addressed to
202.125.11.26
Internal addresses are invisible
to computers on the Internet.
All traffic uses the same
external IP address
assigned by the ISP.
202.125.11.26
HTTP request
AP
Service
controller
NAT can be useful in conjunction with virtual private network (VPN) connections. When two
networks are connected through a VPN tunnel, it may be desirable to obscure the address of
local computers for security reasons.
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