I have some iptables rules in a linux gateway (ubuntu server 12.04) and all works good. I configured a transparent squid proxy and works too. I'm using this rule.
$IPT -t nat -A PREROUTING -p tcp --destination-port 80 \ -j REDIRECT --to-ports 3128
But I must use this server for web development testing and demos, and is rejecting all http requests from internet (eht0). I can access without problems from local network (eth1).
When I comment the rule above. All works again. Why this rule is blocking the http requests from wan network?