I’m trying to use ZT to connect to the KNX/IP interface of home automation system. To do this, I install a mini-PC with ZT inside the customer’s LAN. Now I’m trying to configure UDP port forwarding for port 3671 with iptables. OS Ubuntu 22.04.4 LTS.
Forwarding a port to an IP address within the network does not produce any results. What could be the problem?
iptables -t nat -A PREROUTING -d 0.0.0.0/0 -p udp --dport 3671 -j DNAT --to-destination 192.168.2.20:3671
firewall accepts all packets
My guess is that you are using the -d switch incorrectly, but troubleshooting iptables on Ubuntu is generally difficult.
Revert all iptables changes and try using ufw instead:
In this tutorial, especially note Section 3.2 and ensure that you apply prerequisite changes in the /etc/default/ufw and /etc/sysctl.conf files.