Hi Florian Hi First of all thx for the quick reply. #modinfo nft_ct modinfo: ERROR: Module nft_ct not found. Looks like all the modules are not present. modprobe nft_ct modprobe: FATAL: Module nft_ct not found in directory /lib/modules/4.19.94-rt39-g7028856b05 BR Andy Andreas Hoefler <andreas.hoefler@xxxxxxxxxxxxxxxxxxxxxx> wrote: > Hi > > I am trying to set up a basic connection tracking rule: > #nft list ruleset > table ip filter { > chain input { > type filter hook input priority 0; policy accept; > } > } > # nft add rule filter input ct state established accept > Error: Could not process rule: No such file or directory add rule > filter input ct state established accept > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ works for me on 5.6.18. > cat /proc/config.gz | gunzip | grep NFT # CONFIG_NFT_NUMGEN is not set > CONFIG_NFT_CT=m Does "modinfo nft_ct" work? If its does, is that module loaded? If not, try to load it manually. If that makes the rule add work, then module autoloading is broken on your system for some reason.