does l2tp require ipv6
For remote access VPN connections, IPv6-over-IPv4 traffic across the IPv4 Internet is supported by PPTP and L2TP/IPsec in Windows Vista, Windows Server 2008, Windows XP SP1 or higher, and Windows Server 2003 and by SSTP in Windows Server 2008.or remote access VPN connections, native IPv6 traffic across the IPv6 Internet is supported by L2TP/IPsec in Windows Vista and Windows Server 2008 and by SSTP in Windows Server 2008.