I've just finished to configure a MikroTik RouterOS L2TP Server with RouterOS 3.28 using a public IP address in ether1 interface and a LAN IP address in ether2.
Using this howto http://wiki.mikrotik.com/wiki/MikroTik_ ... IPSec/L2TP I can got to connect to my LAN over L2TP VPN but it only works when my Windows XP client is connected to the internet through a public IP address, but when I am behind a NAT device I cannot connect to my RouterOS VPN Server.
I don't have any trouble If I try to connect to another L2TP server (3com VPN Server) behind the same NAT device.
Someone knows how to resolve this?
Thanks for your help.