About my Firewall Settings - I would like an opinion

[Manuel Gomez <mgdpz1@gmail.com>]

Hi, i would like to read opinions about my firewall settings:


I am using Iptables with Shorewall (frontend) and my configuration is:


- Default Policy: REJECT all connections.


- Rules: Allow DNS (my DNS servers), allow http and https connections 
for servers: www.google.es, ...


So, nobody except these servers can connect with me (inbound and outbound).


This type of configuration is secure?  How could they attack me?


Thank you very much, i appreciate your help.