a) Configure Vyatta Router : see above or Vyatta security refferences (www.vyatta.com)

b) Create WIndows VPN client: see Vyatta security refferences (www.vyatta.com)

c) Enable port/protocols for Windows (remote) client behind firewall

The client does not use a specific application which takes care of oppening ports (forr example cisco VPN client).
You have to open in firewall specific ports as following:

For PPTP VPN client:
Direction:Out
Local: 0-65535
Remote: 1723

For GRE Protocol:
Direction:Both ways
Local: 0-65535
Remote: 0-65535

Random article

• How to Detect Request Coming From Facebook
• Database – Zen Cart
• Create a module – ZenCart
• Google map API Key
• Create rounded corners with CSS
• HTML5 Tag
• Google Places and Yellow Pages
• Developer tips and tricks – CMS Made Simple
• Login, Register in Zencart
• Google Waves