Hi, I tried iptables 1.8 with the new nf_tables back-end using the Debian 1.8.0-1~exp1 package with my firewall script. It seems to properly load most rules, however I am getting an error when negating an interface and using protocol ports, which works fine with classic iptables. Specifically these work OK: # iptables -A INPUT ! -i eth0 -p udp -j ACCEPT # iptables -A INPUT -i eth0 -p udp --dport 5202 -j ACCEPT But when using an interface negation with --sport or --dport it reports an error, here is an example: # iptables -A INPUT ! -i eth0 -p udp --dport 5202 -j ACCEPT iptables v1.8.0 (nf_tables): RULE_APPEND failed (Invalid argument): rule in chain INPUT Thank you.