Nortel Networks 620 User Manual

Configuration via the Command Line Interface

E-DOC-CTC-20051017-0169 v0.1

An example of Auto

ProxyARP

As an example, suppose a VPN server is configured on a SpeedTouch™ with the 
subnet 192.168.1.0 as its private LAN address range. The VPN server is configured 
to distribute Virtual IP addresses to the remote clients in the same range (Virtual IP 
range = 192.168.1.[64-74] ). In this case, automatically a ProxyARP entry is added to 
the ARP table of the SpeedTouch™ as soon as a VPN connection with a VPN client is 
established. The ARP table contents can be monitored with the command ip arplist.

In the output shown above, the entry for 192.168.1.64 is the ProxyARP entry for the 
remote VPN client. The entry for 192.168.1.100 is a locally connected terminal that 
received its IP address from the SpeedTouch™ DHCP server.

If the VPN client is a SpeedTouch™ that uses the dhcp method as virtual IP mapping 
method (see 

), then also here some ProxyARP 

entries are automatically added to the ARP table. Below, you find the ARP table of 
the VPN client SpeedTouch™ of our example.

In the output shown above, the last entry for 192.168.1.0/24 is the ProxyARP entry 
which is added when the VPN connection is established. This entry means that the 
entire subnet is located behind the VPN connection. The entry for 192.168.1.100 is 
an instantiation - marked with (i) - for a single remote terminal. The instantiation is 
made on the moment when there is traffic for this IP address.

=>:ip arplist
Interface

IP-address

HW-address

Type

3

lan1

239.255.255.250

01:00:5e:7f:ff:fa DYNAMIC

3

lan1

192.168.1.100

00:0d:56:1d:f9:ba DYNAMIC

=>

=>ip arplist
Interface

IP-address

HW-address

Type

2

lan1

239.255.255.250

01:00:5e:7f:ff:fa DYNAMIC

2

lan1

10.0.0.1

00:0d:88:65:ca:da DYNAMIC

2

lan1

192.168.1.64

00:0d:88:65:ca:da STATIC

=>