Configuring Vpns; Setting The Vpn Mode - 3Com OfficeConnect User Manual

Configuring VPNs

Virtual private networks (VPN) provide an encrypted connection
(or tunnel) between networks or between a network and a user
over a public network (such as the Internet). Instead of using a
dedicated, real-world connection such as leased line, a VPN uses
virtual connections through the public network. The Secure
Router supports both network to network connections and
network to remote client connections.
There are two modes of operation, pass-through and server. The
Router supports IPSec tunnels, L2TP over IPSec, and PPTP
connections and allows VPN pass-through to enable other secure
devices on your network to set up their own secure connections.
Your Cable/DSL modem and your ISP must support IPSec
pass-through, L2TP over IPSec pass-through or PPTP pass-through
for you to be able to use these protocols.
To allow VPN pass-through, you must configure a virtual server.
See "The Virtual Servers Menu"
configure pass-through protocols.

Setting the VPN Mode

The Router supports three modes of VPN operation:
IPSec Enabled — IPSec (Internet Protocol Security) is a
complex secure protocol with a variety of different encryption
methods. When setting up an IPSec connection between two
devices they must support the same encryption method.
on page 48 for details of how to
L2TP over IPSec Enabled — L2TP over IPSec is a combination
of two protocols. A user is authenticated (using L2TP) and
encrypts data (using IPSec). See
page 59. L2TP does not support gateway to gateway
connections and is only suitable for connecting remote users
PPTP Server Enabled — PPTP (Point-to-Point Tunnelling
Protocol) is an encrypted VPN protocol like IPSec. It is not as
secure as IPSec but is easy to administrate. PPTP does not
support gateway to gateway connections and is only suitable
for connecting remote users.
Enabling IPSec VPN will disable pass-through to IPSec and
L2TP/IPSec Virtual Servers on the LAN. Enabling L2TP over IPSec
will disable pass-through to IPSec and L2TP/IPSec Virtual Servers
on the LAN. Enabling the PPTP server will disable PPTP
pass-through to a Virtual Server on the LAN. Pass-through
outbound from clients on the LAN to servers on the internet is
unaffected.
A VPN Tunnel needs the same protocol on both sides of the
connection. If you are trying to establish an IPSec connection
with another gateway device or with a user, the other gateway
device must support IPSec or the user must have software
installed that supports IPSec VPN.
The VPN Mode menu is shown in
the options by clicking in the appropriate radio button under
VPN Server Setup.
IPSec Configuration
In the IPSec Configuration field, enter This Router's ID as an
Internet IP address or name of the Router that you are
configuring. This value is common across all IPSec connections
58
"L2TP Configuration" on
Figure 59 below. Choose from