According to an interview on http://linuxsecurity.com published in 2003, James Yonan was traveling in Central Asia in days prior to 9/11, 2001 and connecting to his office over Asian or Russian Internet Providers.

The fact that these connections were established over servers in countries with very doubtable security situations made him more and more aware of and concerned about security issues. His research brought the insight that there were two main streams in VPN technology, one promoting security and the other, usability. None of the solutions available at that time offered an ideal blend of both objectives. IPsec and all of its implementations were difficult to set up, but offered acceptable security. But its complex structure made it vulnerable to attacks, bugs, and security flaws. Therefore, the networking approach Yonan found in some of the usability camp's solutions seemed to make more sense to him, leading him to a modular networking model using the TUN/TAP...