Blocking SMB

["Charlie Grosvenor" <charlie@thegrosvenors.fsnet.co.uk>]

Hi
    I am trying to block smb going out of my network using the following
rules.

iptables -A FORWARD -o ppp0 -p tcp --dport 135 -j REJECT
iptables -A FORWARD -o ppp0 -p tcp --dport 136 -j REJECT
iptables -A FORWARD -o ppp0 -p tcp --dport 137 -j REJECT
iptables -A FORWARD -o ppp0 -p tcp --dport 138 -j REJECT
iptables -A FORWARD -o ppp0 -p tcp --dport 139 -j REJECT
iptables -A FORWARD -o ppp0 -p udp --dport 135 -j REJECT
iptables -A FORWARD -o ppp0 -p udp --dport 136 -j REJECT
iptables -A FORWARD -o ppp0 -p udp --dport 137 -j REJECT
iptables -A FORWARD -o ppp0 -p udp --dport 138 -j REJECT
iptables -A FORWARD -o ppp0 -p udp --dport 139 -j REJECT
iptables -A FORWARD -o ppp0 -p udp --dport 445 -j REJECT
iptables -A FORWARD -o ppp0 -p tcp --dport 445 -j REJECT

For some reason this is not working as http://stealthtests.lockdowncorp.com
is able to find out information about my computer using smb for example it
gives me my username that i used to log into windows with.

How can i get the blocking of smb working? Is ther a port that i should
block that i haven't?

Thankyou

Charlie