Originally Posted by Blue_Ice
If I try these rules, then nothing seems to work.
(Bad that the rule get not quoted)
As those rules just block everything this might be the explanation.
Also as saavik said this is just the start. It blocks just everything. So everything else needs to be allowed
iptables -A OUTPUT -p tcp --dport 80 -j ACCEPT
to have at least http going (--dport 80 for HTTP traffic).
Maybe allow 53 on tcp and udp to have some DNS traffic.
and check what services you would like to open up to the outer world.
At least you would need
53 tcp/udp for dns
80/443 tcp for http/https
Maybe check out http://www.netfilter.org/
to get a better view of normal usage of iptables
What I total forgot that iptables STACK
So first deny everything like saavik put in his rules and then allow all you want. First iptables rule of his post.