Nortel 1010 用户指南

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页码 178
140 Chapter 7 Configuring control tunnels
NN46110-500 
 
In this environment, the remote Boston Nortel VPN Router is a control tunnel to 
the local Cleveland Nortel VPN Router. From any system on the Cleveland 
network, you can access the management address for the Boston Nortel VPN 
Router. This allows systems on the Cleveland network to initiate management 
operations on the Boston Nortel VPN Router, such as HTTP, FTP, and Telnet. Yet 
because it is a control tunnel, users on the Cleveland private networks cannot 
exchange packets with users on the private Boston Network. 
Additionally, a user control tunnel is configured so that a remote user can establish 
a control tunnel when using the IPsec client. You create this user account with 
password authentication in the Control Tunnels group using the serial port. 
Restricted mode
The Restricted mode feature prevents management of the Nortel VPN Router 
except through a control tunnel. This limits the scope of management to someone 
who has the proper credentials both to set up the tunnel (if it is an end user) and to 
log in as an administrator (administrative access privileges). Having the proper 
access privileges acts as a level of security. Additionally, since in restricted mode 
you are forced to manage the Nortel VPN Router through a tunnel, you are 
guaranteeing data protection through encryption. 
You enable Restricted mode through the Serial Interface menu or the command 
line interface available through Telnet. In Restricted mode, you can perform the 
key management functions through the control tunnel, including HTTP, FTP, 
SNMP, and Telnet. All other attempts to perform these actions outside of the 
control tunnel will fail. You cannot enter Restricted mode unless there is an active 
control tunnel. This ensures there is a mechanism to manage the Nortel VPN 
Router in restricted mode. 
Nailed-up control tunnels
You may want to have some control tunnels remain up even when there is no 
traffic traversing the control tunnel. This is generally the case for branch office 
versus end user control tunnels. 
Note: If you change any settings to the branch office connection when 
using nailed up tunnels, you must bring down the tunnel for the changes 
to take effect.