Upcoming community maintenance Oct. 27th through Oct. 29th
For more info click here

How to make 2 clients on same VLAN communicate to each other when tunnel-loop-prevention is enabled?


How to make two clients on same VLAN communicate to each other when tunnel-loop-prevention is enabled on tunneled-node configuration at controller?

Whenever we enable tunnel-loop-prevention on controller while we configure tunneled-node, the communication between two tunneled-node client on same VLAN is blocked or dropped.

If the tunneled-node clients are of different VLANs then they can communicate between them even when the tunnel-loop-prevention is enabled on the controller.


To make two tunneled-node client on same VLAN to communicate between them, we need to enable "local-proxy-arp" for the interface VLAN on the controller.

Once it is enabled now the tunneled-node clients on same VLAN can communicate between each other. 


To enable "local-proxy-arp":

Get to the interface of the VLAN on the controller

Example :

(config)#interface vlan 5
(config)#ip local-proxy-arp


To enable tunnel loop prevention on controller

(config)# tunnel-loop-prevention



Show commands:

To check if tunnel-loop-prevention is enabled or disabled

#show tunneled-node config

Tunnelded node Server: Enabled
Tunnel Loop Prevention: Enabled


To check if local-proxy-ap is enabled:

#show interface vlan 5

Look for in the output "ProxyARP enable"



Version history
Revision #:
2 of 2
Last update:
‎08-04-2015 05:39 PM
Updated by:

Thank you for the info.  This is very helpful.  I have another question to add to this.  Once you enable tunnel loop prevention and proxy arp is there anyway to find a loop if one occurs? We have intentially looped the network and we can't seem to figure out the best way to find it.  Thanks ahead of time for any help.