how traffic on loopback works

[ahmad20]

Hello,

How is local generated traffic on loopback different from traffic which goes through physical interfaces?

Does traffic on loopback go through iptables or ipsec tables sad and spd ?

I try this: 'ping -I eth0 <eth0_ip>' but my sniffer catches this again on loopback. What happens ?

Thank you.

[dilbert]

Second question I canot answer, but if the network stack figures out that the target IP address is on the same computer, it sends the traffic by default to the loopback. Otherwise it could simply discard it; what else should it do?

Don't you get a message when pinging like "cannot bind to specific iface" and "operation not permitted"?