Linux Ipsec

• FreeS/WAN, Openswan, strongSwan
  • KLIPS
    
  • pluto
• KAME
  
  • for NetBSD, FreeBSD
  • racoon
    
• isakmpd
  
  • for OpenBSD
  • isakmpd
    
• NETKEY
  
  • Linux builtin ipsec stack, aka native
  • Alexey Kuznetsov and David S. Miller
  • can be used with pluto, isakmpd, racoon, or without any daemon (using manual keying).

[Wiki]Ipsec
http://en.wikipedia.org/wiki/IPsec