System-based opportunistic mode

The system-based opportunistic mode enables HIP communication without the use of the opportunistic library. If the peer does not support HIP, communication falls back on normal TCP communication.

The system-based opportunistic mode is implemented at the HIP firewall. It is enabled with the -o option as shown below:

hipfw -dAo

Following is an example of all the steps to be followed at two peers for using the system-based opportunistic mode between them.

At the responder, one can execute these steps:

1. hipd

2. hipfw -Aod

3. nc -l 1111

At the initiator, one can execute these steps:

1. hipd

2. hipfw -dAo

3. nc <responder-ip> 1111