hi i have setup dial-up connection on Red Hat 8.0 working fine

here is iptables rules that i configured:

iptables -P INPUT ACCEPT
iptables -P OUTPUT ACCEPT
iptables -P FORWARD DROP

echo 1 > /proc/sys/net/ipv4/ip_forward

iptables -t nat -A POSTROUTING -o ppp0 -j MASQUERADE
iptables -A FORWARD -i ppp0 -o eth0 -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -A FORWARD -i eth0 -o ppp0 -j ACCEPT

eth0 is connected to lan via switch

now from another system i can ping to out side of the world

but when i try to access any site from mozilla first it says web site found
waiting for reply and gets hang

i don't know why it is happening plz help me?