this was the suggestion from another forum !! which helped me solve my issue!!
################################################### The security risk is not any individual accessing your proxy, it's the proxy itself. *THAT* is what needs looking at.
However, you can deny access to the proxy to anyone not in 192.168.0.0/24 with this iptables rule - assuming your proxy is on port 3128:
# iptables -I INPUT 1 -s ! 192.168.0.0/24 --dport 3128 -j DROP
G. Stewart - gstewart@spamcop.net #####################################################
Agnello