Re: [solved] hashtable configuration issue

["J. Bakshi" <joydeep@infoservices.in>]

J. Bakshi wrote:

got it :-)


iptables -N syn-flood
iptables -A INPUT -i $IFACE -p tcp --syn -j syn-flood
iptables -A syn-flood -p tcp --syn  -m hashlimit \
--hashlimit 1/sec --hashlimit-burst 4 --hashlimit-htable-expire 300000 \
--hashlimit-mode srcip --hashlimit-name testlimit -j RETURN
# Drop IP bad IP and put then in blacklist
iptables -A syn-flood -m recent --name blacklist --set -j DROP
iptables -A INPUT -j syn-flood




> Dear Marek and all,
>
> First of all my thanks to all of you to make me familiar with the great
> hashtable module. According to Marek's  suggestion I have a ruleset with
> synflood protection along with IP blacklist
>
> ````````````````````
> # default policy drop ##
>
> # accept related , establish ##
>
>
> # Set blacklist #
> echo "blacklist initialization"
> iptables -A INPUT -m recent --name blacklist --rcheck --seconds
> $BLACKLIST_INTERVAL  -j DROP
>
> ## some other anti nmap rule##
>
> ##syncflood protection with IP blacklist ##
>
> iptables -N syn-flood
> iptables -A INPUT -i $IFACE -p tcp --syn -j syn-flood
> iptables -A INPUT -p tcp --syn  -m hashlimit \
> --hashlimit 1/sec --hashlimit-burst 4 --hashlimit-htable-expire 300000 \
> --hashlimit-mode srcip --hashlimit-name testlimit -j RETURN
>
> # Drop bad IP and put themin blacklist ############
> iptables -A syn-flood -m recent --name blacklist --set -j DROP
> iptables -A INPUT -j syn-flood
>
> ## my incoming and outgoing rules ##
>
> ## DROP other ##
> ```````````````````````````````````
>
> But this time firewall totally blocks all incoming connection. If I
> change the RETURN (above) to ACCEPT then then firewall accept *all*
> incoming even the ports are blocked in the firewall !!!   I  am very
> confused. Could any one enlighten me ? I missed something or
> mis-configuration ?
>
>
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