Allow web and ssh connections SSH and web both require out going messages on established tcp connections.
iptables -A OUTPUT -o eth0 -m state –state ESTABLISHED,RELATED -j ACCEPT
Then you need to allow incomming connections on port 80 and 22 and possibly 443
iptables -A INPUT -p tcp -i eth0 –dport 22 –sport 1024:65535 -m state –state NEW -j ACCEPT
iptables -A INPUT -p tcp -i eth0 –dport 80 –sport 1024:65535 -m state –state NEW -j ACCEPT
iptables -A INPUT -p tcp -i eth0 –dport 443 –sport 1024:65535 -m state –state NEW -j ACCEPT