I am investigating the GRE tunnel + IPSec deployment and have some quesitons need help now.

1. By ifconfig gre0 12.0.0.1 12.0.0.2 link1        <- set the local (inner) addrs
Can specify the inner address, that is, the traffic need go through  GRE tunnel. So how to specify more than one traffic
 streams. In my case, I want let multicast also go through the same GRE tunnel.

2. By ifconfig gre0 tunnel 10.25 10.163  can specify the outer address of the GRE tunnel. My question is that can the 
inner and outer IP address be the same?

3. How to monitor the statistics, like the pkt numbers ,of the GRE tunnel?


Thanks

Lei