Membuat Server Centos Menjadi Gateway dan Transparent Proxy dengan Squid

# Hapus semua seting yang sudah ada.
iptables –flush
iptables –table nat –flush
iptables –delete-chain
iptables –table nat –delete-chain
# Set up IP FORWARDing and Masquerading
iptables –table nat –append POSTROUTING –out-interface eth0 -j MASQUERADE
iptables –append FORWARD –in-interface eth1 -j ACCEPT
# Aktifkan packet forwarding di kernel
echo 1 > /proc/sys/net/ipv4/ip_forward
# routing
route add -net 192.168210.0 netmask 255.255.255.0 gw 192.168.200.1 dev eth1

# TAG: http_port
# Usage: port [options]
# hostname:port [options]
# 1.2.3.4:port [options]
#
# The socket addresses where Squid will listen for HTTP client
# requests. You may specify multiple socket addresses.
# There are three forms: port alone, hostname with port, and
# IP address with port. If you specify a hostname or IP
# address, Squid binds the socket to that specific
# address. This replaces the old ‘tcp_incoming_address’
# option. Most likely, you do not need to bind to a specific
# address, so you can use the port number alone.
#
# The default port number is 3128.
#
# If you are running Squid in accelerator mode, you
# probably want to listen on port 80 also, or instead.
#
# The -a command line option will override the *first* port
# number listed here. That option will NOT override an IP
# address, however.
#
# You may specify multiple socket addresses on multiple lines.
#
# options are:
# transparent Support for transparent proxies
# vhost Accelerator using Host directive
# vport Accelerator with IP virtual host support
# vport= As above, but uses specified port number
# rather than the http_port number.
# defaultsite= Main web site name for accelerators.
# urlgroup= Default urlgroup to mark requests
# with (see also acl urlgroup and
# url_rewrite_program)
# protocol= Protocol to reconstruct accelerated
# requests with. Defaults to http.
# no-connection-auth
# Prevent forwarding of Microsoft
# connection oriented authentication
# (NTLM, Negotiate and Kerberos)
# tproxy Support Linux TPROXY for spoofing
# outgoing connections using the client
# IP address.
#
# If you run Squid on a dual-homed machine with an internal
# and an external interface we recommend you to specify the
# internal address:port in http_port. This way Squid will only be
# visible on the internal address.
#
# Squid normally listens to port 3128
http_port 3128 transparent

iptables –table nat –append PREROUTING -i eth1 -p tcp –dport 80 -j REDIRECT –to-port 3128

Dari browser di komputer client dengan isian proxy di kosongkan (tanpa proxy) lakukan browsing ke www.uii.ac.id

telnet 192.168.210.1 80
Trying 192.168.210.1…
Connected to 192.168.210.1.
Escape character is ‘^]’.
kemudian tuliskan alamat website yang akan dibuka, misalnya www.uii.ac.id
get http://www.uii.ac.id

maka berikutnya akan muncul isi text dari www.uii.ac.id