1NFBPF_COMPILE(8)                iptables 1.8.3                NFBPF_COMPILE(8)
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NAME

6       nfbpf_compile - generate bytecode for use with xt_bpf
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SYNOPSIS

9       nfbpf_compile [ LLTYPE ] PROGRAM
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11       LLTYPE := { EN10MB | RAW | SLIP | ...  }
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DESCRIPTION

15       The nfbpf_compile utility aids in generating BPF byte code suitable for
16       passing to the iptables bpf match.
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OPTIONS

20       LLTYPE Link-layer header type to operate on. This is a name as defined
21              in <pcap/dlt.h> but with the leading DLT_ prefix stripped. For
22              use with iptables, RAW should be the right choice (it's also the
23              default if not specified).
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26       PROGRAM
27              The BPF expression to compile, see pcap-filter(7) for a descrip‐
28              tion of the language.
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EXIT STATUS

32       The program returns 0 on success, 1 otherwise.
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EXAMPLE

36       Match incoming TCP packets with size bigger than 100 bytes:
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38               bpf=$(nfbpf_compile 'tcp and greater 100')
39               iptables -A INPUT -m bpf --bytecode "$bpf" -j ACCEPT
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41The description of bpf match in iptables-extensions(8) lists a few more exam‐
42ples.
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SEE ALSO

46       iptables-extensions(8), pcap-filter(7)
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50iptables 1.8.3                                                NFBPF_COMPILE(8)