Support for Virtual Private Networks (VPNs)
29
Support for Virtual
Private Networks
(VPNs)
Through its support of the Point-to-Point Tunnel Protocol (PPTP), the Dual 56K
LAN Modem allows users on any workstation attached to the LAN Modem to
communicate with a remote private network over the Internet using a Virtual
Private Network (VPN) tunnel, provided the necessary client software is installed
on the user’s workstation.
Although the LAN Modem allows for the transparent passage of VPN tunnel data
from a computer on its LAN side to its WAN side, the LAN Modem cannot itself
initiate or terminate a tunnel. In other words, the LAN Modem does not encrypt or
encapsulate data on the outgoing side of the VPN connection, nor does it act as a
tunnel terminator to unpack tunnel packets on the incoming side.
VPN tunnels are a private, secure means by which content-sensitive data that uses
any routing protocol can be transported over the public, IP-routable-only Internet.
Because a VPN tunnel is established through a local call to an Internet Service
Provider, a user connecting to a remote Private Network through a VPN tunnel can
eliminate long distance charges that might otherwise be incurred from dialing
directly to the remote private network.
Figure 14 shows a VPN tunnel connection to a remote private network using a
single, locally-dialed ISP call.
Figure 14
VPN Tunnel Connection to a Remote Private Network via an ISP
To create a VPN tunnel from a workstation attached to the Dual 56K LAN Modem,
no special configuration of the LAN Modem is required. The client workstation
must, however, have the appropriate software, and a tunnel server must be set up
at the remote private network.
Basic instructions for setting up and initiating a VPN tunnel from a client
workstation are provided in Appendix C, “Creating a Virtual Private Network
(VPN) Tunnel.”
Public telephone
network
Dual 56K LAN Modem
Workstation
with PPTP
client software
PPTP Tunnel
server
VPN tunnel
Corporate office
LAN
Mor
e c
onn
ect
ed
3
Com
Sta
tus
Re
set
TX
D
D
1 2
1
2
4
3
1/2
3/4
3 4
RX
TX
LK
RX
LA
N
Re
mo
te
Acc
ess
Sys
tem
15
00
WA
N
CO
Po
we
r
BR
I IS
DN
U
AN
AL
OG
SL
OT
1
SL
OT
2
ST
AC
KN
ET
CO
NS
OL
E
SU
PE
R
STA
CK
3
Com
Alert
Power
Message
RD
AA
CD
SD
OH
RD
AA
CD
SD
OH
1
TX
COLL
2
3
4
OfficeConnect
Dual 56k LAN Modem
LAN Status
MODEM 2
MODEM 1
Internet
Summary of Contents for 3C888 - OfficeConnect Dual 56K LAN Modem Router
Page 10: ...GLOSSARY 3COM CORPORATION LIMITED LIFETIME WARRANTY REGULATORY AND APROVAL INFORMATION ...
Page 30: ...30 CHAPTER 2 DUAL 56K LAN MODEM FUNCTIONALITY DESCRIPTION ...
Page 46: ...46 CHAPTER 4 INSTALLING THE DUAL 56K LAN MODEM ...
Page 58: ...58 CHAPTER 5 CONFIGURING THE DUAL 56K LAN MODEM FOR INTERNET ACCESS ...
Page 124: ...124 CHAPTER 9 PLACING RECEIVING AND DISCONNECTING CALLS ...
Page 136: ...136 CHAPTER 10 TROUBLESHOOTING AND MAINTENANCE ...
Page 146: ...146 APPENDIX A NETWORKING PRIMER ...
Page 154: ...154 APPENDIX D FACTORY DEFAULTS ...
Page 156: ...156 APPENDIX E SPECIFICATIONS ...
Page 166: ......