Digi TransPort, Руководство пользователя

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PPTP parameters
Digi TransPort User Guide 445
PPTP parameters
The Point-to-Point tunneling protocol (PPTP) is a common way of creating a VPN tunnel to a
Microsoft Windows™ server.
PPTP works by ending a regular PPP session to the peer encapsulated by the Generic Routing
Encapsulation (GRE) protocol. A second session on TCP port 1723 is used to initiate and manage
the GRE session. PPTP connections are authenticated with Microsoft MSCHAP-v2 or EAP-TLS. VPN
traffic is protected by MPPE encryption. PPTP does not work with GPRS/HSDPA mobile operators
that assign a private IP address and then apply NAT to the traffic before it leaves their network.
This because the server tries to build a tunnel back to the router on port 1723 but fails when the
traffic is blocked by the mobile operator’s firewall.
PPTP n parameters
Description
An identifier for the router.
Remote Host a.b.c.d
The IP address of the remote host, such as the device that will terminate the PPTP connection.
Use Interface x,y
The interface to be used for the PPTP tunnel is selected from this drop-down list, the text box
next to it is for the interface instance. Specifying these parameters allow the router to raise
the interface should it be disconnected. The interface options are:
• Auto
• PPP
• Ethernet
Accept incoming PPTP connections
When enabled, the router acts as a PPTP server and accepts incoming VPN connections.
Enable Server mode
When enabled, the router sends call_out call requests to the remote device. In the default
state which is unchecked, the router sends a call_in request to the remote device.