Note: Some of the listed features are currently untested.

This Linux implementation features
- ICMP "fragmentation needed" filter (for the MTU problem)
- Firewalling hooks: ENskip will catch all packets if running on a
  router. I.e. you will get a SKIP firewall gateway which handles
  the authentication/encryption in behalf of its dumb inside clients.
  No tunneling is required, but it can be configured.
- User level socket options:
  Users can request stronger authentication/encryption using
  setsockopt calls (see /usr/include/linux/ipsec.h).
  If encryption/authentication is not mandatory, you can turn it
  off (e.g. for programs which use their own security layer).
- Interaction and compatibility with future versions of the 
  sf Firewall software.
- Interoperability with other SKIP versions. See 
  http://www.rsa.com/rsa/SWAN/

// 04 Dec 1996 Robert Muchsel <muchsel@acm.org>
