An interesting and, for me, timely article. One aspect of VPNs not really covered was that of authentication. Many (most?) VPNs require certificate authentication. That's fine for connecting two networks, but for road warrior use it's both overkill and complex. What a lot of organisations want is the ability for a road warrior to access an existing Linux server and be authenticated by PAM or possibly the Samba backend. No complex per-laptop certificate generation and installation. Less secure? Yes, maybe, but Open Source is about choice, and some organisations choose ease of implementation over the ultimate in security.