There is a problem.... you should get , after all the iptables command help, something like:
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[...]
[!] --fragment -f match second or further fragments only
--modprobe=<command> try to insert modules using this command
--set-counters PKTS BYTES set the counter during insert/append
[!] --version -V print package version.
MARK target v1.3.7 options: <<-- you should have that !!!!!!
--set-mark value Set nfmark value
--and-mark value Binary AND the nfmark with value
--or-mark value Binary OR the nfmark with value
root@OpenWrt$
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now, could you do ` ls -l /usr/lib/iptables/ `
and past me the result, thanks