Virtual private networking

1. Communications protocol

1. SSTP
2. IPsec
3. L2TP
4. L2TPv3
5. PPTP
6. Split tunneling
7. SSL/TLS (Opportunistic: tcpcrypt)

2. Free software

1. Cloudvpn
2. FreeLAN
3. FreeS/WAN
4. Libreswan
5. n2n
6. OpenConnect
7. OpenIKED
8. Openswan
9. OpenVPN
10. Social VPN
11. SoftEther VPN
12. strongSwan
13. tcpcrypt
14. tinc
15. VTun
16. WireGuard
17. Shadowsocks

3. Vendor-driven protocols 供应商驱动的协议

1. Layer 2 Forwarding Protocol
2. DirectAccess

4. Proprietary software 专有软件

1. Avast SecureLine VPN
2. Check Point VPN-1
3. Cisco Systems VPN Client
4. LogMeIn Hamachi
5. Microsoft Forefront Unified Access Gateway
6. Hola
7. Tunnelbear
8. NordVPN
9. SaferVPN
10. ExpressVPN
11. ProtonVPN
12. PureVPN
13. VPN.ht
14. Private Internet Access
15. AzireVPN
16. AceVPN

5. Risk Vectors 风险向量

1. Content-control software
2. Deep content inspection
3. Deep packet inspection
4. IP address blocking
5. Network enumeration
6. Stateful firewall
7. TCP Reset
8. VPN blocking