M2M IDG500AM-0T001 User Manual page 208

M2M Cellular Gateway
Scenario Application Timing
Above diagram illustrates the Security Gateway 2 or the mobile device playing the PPTP
VPN client role. The PPTP tunnel is established by the PPTP client making the tunnel
connection request initiation and the Security Gateway 1 in Network‐A of headquarters
serves as the PPTP VPN server responding to the request. Once the tunnel has been
established, all client hosts behind the Security Gateway 2 or the mobile device can
access the resources in the Intranet of Network‐A at headquarters via this established
PPTP tunnel. Usually, these hosts at PPTP client peer access the Internet directly via the
WAN interface of Security Gateway 2. Only the packets whose destination is in the
dedicated subnet to Network‐A will be transferred via the PPTP tunnel. But if PPTP
client peer is configured to all packets are delivered via the PPTP tunnel, as shown in
the diagram by configuring the PPTP tunnel is the default gateway at PPTP client peer,
the Internet accessing packets will be also sent to the Security Gateway 1 in Network‐A
and be re‐transferred to the Internet. That means the Internet accessing of PPTP Client
peer is also controlled by the Security Gateway 1, the PPTP VPN server.
Scenario Description
PPTP Tunneling is a Client and Server based tunneling technology.
Index skipping is used to reserve slots for new function insertion, when required.
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