From: bukys @
>Many or most of the commercial firewall vendors offer encrypted IP
>tunnel support for building distributed private networks over the
>I'd like to know whether there is any interoperability (yet) among these
>products, how well the protocol is documented, and whether there
>are free reference implementations. Is there any effort to standardize
>(ie within IETF)?
The IETF standard for this (and any other Encrypted/Authenticated IP
in IP encapsulation applications) is called IPSec -- see RFCs 1825-1829.