• SSL based VPNs: Low Latency, Vulnerable to RST attacks)

• Custom VPN clients: Nortel, Cisco, Windows (hardly interop, Usuall broken behind NAT)

• Unix hacks: stunnel (see abobe), CIPE (cracked)

• Microsoft hack: LT2P (IPsec with glue to use RAS)

• IPsec with RFC extensions X.509: Certificates XAUTH: user/password IKEv2 (Advanced options negotiations)

Notes: