Hello, I am developing golang nftables libraryI am debugging nftables set with elements defining intervals. I compare what gets generated by nfl command and strace of my code. Based on the output of this command: sudo nft --debug all add rule ipv4table ipv4chain-1 ip daddr { 192.16.0.0/16, 10.16.0.0/16 } return It seems nft sets up NFTNL_SET_KEY_TYPE (0x4) as 0x2 and I cannot find anywhere what it means. {{nla_len=8, nla_type=0x4}, "\x00\x00\x00\x02"}, When I decode strace generated for my code, it always gets set to x01 {{nla_len=8, nla_type=0x4}, "\x00\x00\x00\x01"}, I would really appreciate a pointer to where key types are defined and also which flags and or expressions are needed for sets with intervals. Thank you Serguei Full decode below: {{len=108, type=NFNL_SUBSYS_NFTABLES<<8|NFT_MSG_NEWSET, flags=NLM_F_REQUEST|NLM_F_CREATE, seq=1, pid=0}, {nfgen_family=AF_INET, version=NFNETLINK_V0, res_id=htons(0), [ {{nla_len=14, nla_type=NFNETLINK_V1}, "\x69\x70\x76\x34\x74\x61\x62\x6c\x65\x00"}, NFTA_SET_NAME = 0x2 {{nla_len=12, nla_type=0x2}, "\x5f\x5f\x73\x65\x74\x25\x64\x00"}, NFTA_SET_FLAGS = 0x3 {{nla_len=8, nla_type=0x3}, "\x00\x00\x00\x07"}, NFTA_SET_KEY_TYPE = 0x4 {{nla_len=8, nla_type=0x4}, "\x00\x00\x00\x07"}, NFTA_SET_KEY_LEN = 0x5 {{nla_len=8, nla_type=0x5}, "\x00\x00\x00\x04"}, NFTA_SET_ID = 0xa {{nla_len=8, nla_type=0xa}, "\x00\x00\x00\x02"}, NFTA_SET_DESC = 0x9 {{nla_len=12, nla_type=NLA_F_NESTED|0x9}, "\x08\x00\x01\x00\x00\x00\x00\x05"}, NFTA_SET_USERDATA = 0xd {{nla_len=16, nla_type=0xd}, "\x00\x04\x02\x00 \x00\x00\x02\x04 \x01\x00\x00\x00"} ] }, {{len=164, type=NFNL_SUBSYS_NFTABLES<<8|NFT_MSG_NEWSETELEM, flags=NLM_F_REQUEST|NLM_F_CREATE, seq=1, pid=0}, {nfgen_family=AF_INET, version=NFNETLINK_V0, res_id=htons(0), [ NFTA_SET_NAME = 0x2 {{nla_len=12, nla_type=0x2}, "\x5f\x5f\x73\x65\x74\x25\x64\x00"}, NFTNL_SET_KEY_TYPE = 0x4 < ==========================. It is nla type, but I cannot find what type 0x2 means, we always used 0x1 {{nla_len=8, nla_type=0x4}, "\x00\x00\x00\x02"}, {{nla_len=14, nla_type=NFNETLINK_V1}, "\x69\x70\x76\x34\x74\x61\x62\x6c\x65\x00"}, {{nla_len=108, nla_type=NLA_F_NESTED|0x3}, " \x18\x00\x01\x80\x08\x00\x03\x00\x00\x00\x00\x01\x0c\x00\x01\x80\x08\x00\x01\x00\x00\x00\x00\x00\x10\x00\x02\x80\x0c\x00\x01\x80\x08\x00\x01\x00\x0a\x10\x00\x00\x18\x00\x03\x80\x08\x00\x03\x00\x00\x00\x00\x01\x0c\x00\x01\x80\x08\x00\x01\x00\x0a\x11\x00\x00\x10\x00\x04\x80\x0c\x00\x01\x80\x08\x00\x01\x00\xc0\x10\x00\x00\x18\x00\x05\x80\x08\x00\x03\x00\x00\x00\x00\x01\x0c\x00\x01\x80\x08\x00\x01\x00\xc0\x11\x00\x00"} ] },