Building SSH VPNs with OpenSSH
Very Painless Networks
OpenSSH VPN technology, installed by default on most Linux, BSD, and Unix systems, lets you mix and match different clients and servers easily.
When it comes to VPN performance, the problems used to revolve around having enough CPU power to encrypt and decrypt network traffic (watching a Pentium III struggle with 100Mb traffic was always fun). Nowadays, CPU power is cheap, and now with Intel AES-NI and other vendors supporting AES with native instructions, the good news is that most systems can easily keep up with a gigabyte or more of encrypted traffic. One of the biggest performance problems faced by VPNs now is ISPs that either shape (that is to say they slow down) VPN traffic or block it completely.
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