3Com Router User Manual

Display and Debug L2TP 617
of each VPN connection can be guaranteed. The maximum number of sessions 
can be configured at either LNS or LAC, and the smaller one is valid.
Perform the following configurations in system view.
Ta b l e 685   Configure the Maximum Number of L2TP Sessions
By default, the maximum number of L2TP sessions is 1000.
Given that a certain number of sessions have existed on the router, the system will 
display the information indicating misconfiguration if the l2tp session-limit...

618CHAPTER 43: CONFIGURING L2TP 
II. Networking diagram
Figure 183   Networking diagram of NAS-originated VPN
III. Configuration procedure
1Configuration at the LAC (NAS) side:)
aConfigure username and password (when dialing in Windows2000).
[Router-LAC] local-user lac service-type ppp password simple lac
bImplement local AAA authentication on VPN user.
[Router-LAC] aaa-enable
[Router-LAC] aaa authentication-scheme ppp default local
[Router-LAC] aaa accounting-scheme optional
cConfigure the IP address of...

L2TP Configuration Examples619
dConfigure the IP address of Serial0 interface of LNS.
[Router-LNS] interface serial 0
[Router-LNS-Serial0] ip address 192.167.0.1 255.255.255.0
eConfigure the Virtual-Template-related information.
[Router-LNS] interface virtual-template 1
[Router-LNS-Virtual-Template1] ip address 192.168.0.1 255.255.255.0
[Router-LNS-Virtual-Template1] ppp authentication-mode chap
[Router-LNS-Virtual-Template1] remote address pool 1
fEnable L2TP service and configure a L2TP group....

620CHAPTER 43: CONFIGURING L2TP 
Figure 185   Internet Connection Wizard (1)
■Click  and input the telephone number at the NAS side in the popup 
dialog box (if it is a local telephone number, you should deselect “Use area 
code and dialing rules”), as shown in the following figure. 

L2TP Configuration Examples621
Figure 186   Internet Connection Wizard (2)
■Click  and input username and password (such as the username lac and 
password lac) in the popup dialog box so as to access ISP. The input contents 
must be the same as the configuration at the NAS side, as shown in the 
following figure. 

622CHAPTER 43: CONFIGURING L2TP 
Figure 187   Internet Connection Wizard (3)
■Click  and input the name of dialup connection (such as “Connection to 
660046”) in the popup dialog box, as shown in the following figure.
Figure 188   Internet Connection Wizard (4) 

L2TP Configuration Examples623
■Click  and deselect To connect to the Internet immediately, select this 
box and then click Finish in the popup dialog box, as shown in the following 
figure.
Figure 189   Internet Connection Wizard (5)
■Click  and double click “Connection to 66046” icon, then after 
inputting the username and password, you can dial up to access NAS. As 
receiving the call, NAS will establish a tunnel and session to LNS, as shown in 
the following figure. The input username and password...

624CHAPTER 43: CONFIGURING L2TP 
Figure 190   Connect to “Connection to 66046”
To determine the IP address assigned to your computer by the LNS, use the 
DOS-based command ipconfig.
Client-originated VPN 
NetworkingI. Networking requirements
After connecting to the Internet, the VPN user originates request for connecting 
Tunnel. At receiving the request, LNS establishes a Tunnel with the VPN, so as to 
transmit data between the user and the company headquarters.
LAC (NAS) and LNS are connected to a 3Com...

L2TP Configuration Examples625
cConfigure the IP address of Serial1 interface at LAC side.
[Router-LAC] interface serial 1
[Router-LAC-Serial1] ip address 192.167.0.2 255.255.255.0
dConfigure BDR parameters.
[Router-LAC] dialer-rule 1 ip permit
[Router-LAC] interface async 2
[Router-LAC-Async2] async mode protocol
[Router-LAC-Async2] link-protocol ppp
[Router-LAC-Async2] ip address 192.170.0.1 255.255.255.0
[Router-LAC-Async2] ppp authentication-mode chap
[Router-LAC-Async2] remote address pool 1...

626CHAPTER 43: CONFIGURING L2TP 
■Search for HKEY_LOCAL_MACHINE, System, CurrentControlSet, Services, 
Rasman and Parameters level by level in the register in the left. Click 
, and click in the blank space in the right window. Choose 
{Create/Double byte value} and create a register value (name: ProhibitIPSec, 
value:1), then restart Windows2000.
■Create a dialup connection and a VPN connection in Windows2000 operation 
system. The way to create a dialup connection is the same as that introduced in 
the...