Previously I have posted about installation proxy server with squid3 on Ubuntu Server 12.04, on this post I’ll shown How to Set up/Configure Squid3 as Transparent Proxy. by activate squid3 as Transparent Proxy you no longer need to configure all the machines on your network to connect to Squid proxy server manually. All traffic will be routed to the Squid listening port automatically and your Ubuntu Server will act as routers.
Follow the guide Setup Transparent Proxy Server with Squid3 on Ubuntu server 12.04 LTS
Step 1. Make sure squid3 is installed correctly on ubuntu server, you can found tutorial squid3 the installation here
Step 2. Configure network interfaces with static IP address, on this case proxy server using 2 network card
sudo nano /etc/network/interfaces
auto eth0 iface eth0 inet static address 192.168.1.10 netmask 255.255.255.0 network 192.168.1.0 broadcast 192.168.1.255 gateway 192.168.1.1
post-up iptables-restore < /etc/iptables.up.rules
auto eth1 iface eth1 inet static address 192.168.2.10 netmask 255.255.255.0 network 192.168.2.0 broadcast 192.168.2.255
Step 3. Edit file /etc/squid/squid.conf, add the word “transparent” on “http_port 3128”
# NETWORK OPTIONS # ————— # http_port 3128 transparent
Change IP address on options “acl localnet src 192.168.1.0/24 # Your network here”
acl localnet src 192.168.2.0/24 # LAN Ip Address
save and exit.
Step 4. Edit /etc/sysctl.conf
sudo nano /etc/sysctl.conf
Replace with configuration below:
net.ipv4.ip_forward=1 net.ipv6.conf.all.forwarding=1
Save and exit
Step 5. define IPTABLE rules for port forwarding with Editing /etc/iptables.up.rules,
sudo nano /etc/iptables.up.rules
*nat -A PREROUTING -i eth1 -p tcp -m tcp --dport 80 -j DNAT --to-destination 192.168.2.10:3128 -A PREROUTING -i eth1 -p tcp -m tcp --dport 80 -j REDIRECT --to-ports 3128 -A POSTROUTING -s 192.168.2.0/24 -o eth0 -j MASQUERADE COMMIT
Save and exit..
Step 6. Edit /etc/rc.local, and add this script on end of file
iptables -t nat -A POSTROUTING -s 192.168.2.0/24 –o eth0 -j MASQUERADE
Step 7. Restart squid3 and network
sudo /etc/init.d/squid3 restart && sudo /etc/init.d/networking restart
On client set IP address manually:
IP address : 192.168.2.11 Netmask: 255.255.255.0 Gateway: 192.168.2.10 DNS: 192.168.2.10 # or you can use Google DNS 8.8.8.8, 8.8.8.4;
Tags: #Proxy Server #Squid3 #Transparent Proxy
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