Transparent proxy in Vagrant

Setup a transparent proxy with squid3 and vagrant.

When you play with Vagrant boxes or Dockers, a lot of files will be downloaded from internet again and again. For example, every time you run apt-get update, it will download a set of files. The setup process will be much faster if these files can be cached in local network. In this case, a transparent proxy can be very helpful.

How it works

Two Vagrant boxes will be created. Squid 3 is install in one box called squid, and another box called client, is an example to demonstrate how to use the proxy.

The "squid" box has two NICs. The default NIC is used to access internet, while a private_network with IP address 172.28.128.200 will be the gateway of clients.

After these boxes are up, you need to login the client box, change the default gateway with command change-gateway, then most HTTP request will be cached.

Route table can be verified with this command, netstat -r:

root@client:~# netstat -r
Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
default         localhost       0.0.0.0         UG        0 0          0 eth1
10.0.2.0        *               255.255.255.0   U         0 0          0 eth0
172.28.128.0    *               255.255.255.0   U         0 0          0 eth1

To check if the proxy is working, initiate some HTTP requests from "client" box:

curl -v http://bing.com
curl -v http://bing.com

There will be following content in /var/log/squid3/access.log on "squid" box:

vagrant@squid:~$ sudo tail -f /var/log/squid3/access.log
1446885198.469    784 172.28.128.202 TCP_MISS/301 395 GET http://bing.com/ - HIER_DIRECT/204.79.197.200 -
1446885203.531      1 172.28.128.202 TCP_MEM_HIT/301 401 GET http://bing.com/ - HIER_NONE/- -

Enjoy it!

from  https://github.com/YanhaoYang/transparent-proxy-with-squid3-and-vagrant