I answer myself:
possible solution:
iptables -t nat -A PREROUTING --dst YOUR_LOCAL_IP -p tcp --dport 1880 -j DNAT --to-destination 192.168.3.1
I answer myself:
possible solution:
iptables -t nat -A PREROUTING --dst YOUR_LOCAL_IP -p tcp --dport 1880 -j DNAT --to-destination 192.168.3.1