Starting with Windows 2000, Microsoft enhanced DUN with an L2TP over IPsec VPN client. By default, every Windows VPN connection attempts to negotiate L2TP over IPsec first, then falls back to PPTP. However, connections can be explicitly configured to use PPTP or L2TP only. For example, on Windows XP, open the VPN connection's Properties panel, choose the Network tab, and pick either L2TP or PPTP under "Type of VPN."
Windows Servers can be used as VPN gateways (e.g., NT for PPTP, 2000 for PPTP or L2TP). Alternatively, SOHO firewall appliances can also used as IPsec or PPTP VPN gateways -- for example, see the Watchguard SOHO6 or CyberGuard SnapGear SG530. Security appliances can be easier to install and maintain than trying to keep a general purpose Windows Server patched and hardened as your VPN gateway.
This was first published in July 2004