Help with IPTABLES

[tomv]

Hi I need help :-)
my pc(running vista) is behind WL500gP which runs firewall(ip tables)

the post firewall script looks like this:
#block everything
iptables -I FORWARD 1 -j DROP
#routing for established connections
iptables -I FORWARD 1 -m state --state ESTABLISHED,RELATED -j ACCEPT

#DNS allowed
iptables -I FORWARD 1 -p tcp --dport 53 -j ACCEPT
iptables -I FORWARD 1 -p udp --dport 53 -j ACCEPT
# ping allowed
iptables -I FORWARD 1 -p icmp -j ACCEPT

#www alloved
iptables -I FORWARD 1 -p tcp --dport 80 -j ACCEPT
iptables -I FORWARD 1 -p tcp --dport 8080 -j ACCEPT
iptables -I FORWARD 1 -p tcp --dport 443 -j ACCEPT

and some other ports like pop, imap ...

The problem is that i cant open some web pages for example www.microsoft.com (i cant update my vista) and some more.
most of the others pages are working fine.
I can ping the page and the name is resolved to ip adress but i cant open it in browser (opera,ie) if i open this page in Lynx -installed on asus- the page can be shoven.

I think the problem is in some other port which must be open but dunno which one. If i open microsoft page throught www.anonymouse.org its working fine.

Any advice? I have been googling all week but now im lost :-(

[Zyxmon]

Try to make MTU value smaller for your WAN connection. Or make MTU smaller on your pc. Search Google - how to do it on Vista.