Subject: Question about IP-in-IP tunneling

From: [email-masked]
Date: Thu, 26 Feb 2009 13:07:02 -0800

A question for the IP tunneling experts:

For IP-in-IP tunneling, what are the cases when IPROTO_IPIP (4) is used 
in the protocol field of the outer IP header and the cases when 
IPPROTO_IPV6 (41) is used instead?

thanks,
--santwona