Secure Socket Tunneling Protocol (SSTP) is a form of VPN tunnel that provides a mechanism to transport PPP traffic through an SSL channel. SSL provides transport-level security with key-negotiation, encryption and traffic integrity checking. The use of TCP port 443 should increase the chances that SSTP will pass through most firewalls and proxy servers. SSTP servers must be authenticated during the SSL phase. SSTP clients can optionally be authenticated during the SSL phase, and must be authenticated in the PPP phase. The use of PPP allows support for common authentication methods, such as EAP-TLS and MS-CHAP. It is currently available in Windows Server 2008 and Windows Vista SP1 .Vigor2950 series with SSTP VPN solutions.

IPSec VPNs have been being prevalent method of offering secure remote access to the business network. The establishment of IPSec VPNs can be tedious and complicated even though they may be cheap for fixed site-to-site secure tunnels. However, the IPSec VPNs are less appealing for mobile clients. It is much easier for mobile users to implement SSL VPNs because all they need is a standard web browser to securely access the company resources over HTTPS. In the past, the SSL-VPN appliances were far more expensive option with price tags in the high figure range. DrayTek provides SSL VPN services at a price that makes them highly suited to small businesses and medium-size enterprises.