try add this to the top of your firewall filter rules
add action=drop chain=forward-from-internet comment=IPTEST log-prefix="IP MAIL BLOCK" \ src-address-list=IP_TEST
not sure why you are using this jump rule but all the other rules on forward chain are still unchainged, so they will not apply to forward chain, and no filter rules are currently on this forward-from-internet chain, which means you have no firewall to protect your LAN.
basicly, input chian, is traffic heading towards the router itself
forward chian, is traffic going through the router, so that is from LAN to internet, and from Internet to LAN.