Squid: how to block external IP adresses from accessing your squid server

If you are facing a problem of open proxy i.e you see in your logs
public ipaddres accessing your server then you nee to only allow your
local clients from accessing you machine !!

bellow is the rule you need to add in the iptabesl

iptables -t nat -D PREROUTING -s ! 192.168.0.0/24 -p tcp --dport 3128 -j DROP

save the file

and it should work

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