iptables -I FORWARD -p tcp --dport 1863 -j REJECT
iptables -I FORWARD -p udp --dport 1863 -j REJECT
and then reload by using command
./rc.firewall.local reload
iptables -I FORWARD -p tcp --dport 1863 -j REJECT
iptables -I FORWARD -p udp --dport 1863 -j REJECT
./rc.firewall.local reload