SSL/TLS VPN
Tunnels that ride the same TLS everyone already allows.
How widely is it used?
Common in production todayHeavily used in enterprises because TCP/443 survives restrictive networks.
How it works
The tunnel is established inside a TLS session, typically on TCP 443, so to a firewall it looks much like ordinary HTTPS traffic.
Connects
User/device → VPN gateway
Protocols
TLS, OpenConnect, OpenVPN, SSTP
Typical users
Enterprises, Remote users on restrictive networks
Main use case
Remote access from hotel, airport and captive-portal networks.
Advantages
- Passes through firewalls and NAT reliably
- Reuses familiar certificate infrastructure
Limitations
- TCP-over-TCP hurts throughput
- Features vary widely between implementations