Please Provide me with a Step by Step Firewall Rule Creaton Tutorial for l2tp/IPsec remote access

Question

Hey there Folks! 
 I came from Linux Server world where everything is plain and simple! I am a bit Overwhelmed by the Graphical User Interface and i am not be able to open Ports on my XG for IPSEC / l2tp connections 
 
 i am pretty sure i configured everything right under the VPN Section already and created and added some local users for l2tp connections 
 but i get mainly two errors in the log: 
 
 1. 
 est-p1-am: response to establishment request from xxx.xxx.xxx.xxx failed. there is no active connection is defined for this peer OR verify ID configuration at both ends 
 2. 
 est-p1: system did not accept any proposal received. need to reconfigure the connection on either of the ends 
 
 i think the first one has something to do with port forwarding 
 the thing is when i want to add some rules into the firewall it just let me choose between some templates but i cant choose the classical way some ports for source and destination.... 
 i feel kinda stupid because i set several working vpn connections up in my life...just with this sophos stuff not 
 the connections are mainly used for mac os client systems... 
 
 so please provide me with a small step by step tutorial for setting up my own fw rules 
 
 i saw another step by step request here but it didnt provide me with the exact steps what i needed.... 
 
 thank you so much ear sophos community

PGP · Accepted Answer

Thank you for all your responses. Finally got it working with the help of sophos support. Fortigate unit was behind nat so the remote address had to be entered into remote ID in order to allow. Had to make fortigate and Sophos to use AES128/256 MD5 and 2DES MD5. All worked after making the changes. Thank you again for your support.