While configuring a router, we decided to have privoxy and polipo work together in order to cache web-content in order to speed up browsing.

privoxy.conf

confdir /etc/privoxy
logdir /var/log
actionsfile standard.action  # Internal purpose, recommended
actionsfile default.action   # Main actions file
actionsfile user.action      # User customizations
filterfile default.filter
logfile privoxy_logfile
jarfile privoxy_jarfile
trust-info-url  http://www.example.com/why_we_block.html
trust-info-url  http://www.example.com/what_we_allow.html
#admin-address privoxy-admin@example.com
#proxy-info-url http://www.example.com/proxy-service.html
debug   1    # show each GET/POST/CONNECT request
debug   4096 # Startup banner and warnings
debug   8192 # Errors - *we highly recommended enabling this*
listen-address  192.168.1.1:8118
toggle  1
enable-remote-toggle  0
enable-edit-actions 0
enable-remote-http-toggle  0
accept-intercepted-requests 1
forward / 192.168.1.1:8123
permit-access  192.168.1.0/24
buffer-limit 4096

where 192.168.1.1 is the router network IP address.

We set-up a quota for Polipo since by design it is not aware of free space:

mkdir -p /home/polipo
dd if=/dev/zero of=/home/polipo/polipo.img bs=1M count=256
mkfs.ext3 /home/polipo/polipo.img

where count is the value in MB. In this case we use 256MB of disk space dedicated to cache.

Now we create a loopback device for /home/polipo/polipo.img

losetup /dev/loop/0 /home/polipo/polipo.img
mount -t ext3 /dev/loop/0 /home/polipo

and make that persistent by adding a line to fstab:

/dev/loop/0  /home/polipo ext3  noatime 0 0

finally, we create the polipo configuration file:

polipo.conf

proxyAddress = "192.168.1.1"    # IPv4 only
allowedClients = "192.168.1.1"
cacheIsShared = true
dnsQueryIPv6 = no

iptables -t nat -A PREROUTING -i br-lan -p tcp --dport 80 -j DNAT --to 192.168.1.1:8118

where br-lan is the lan interface; in this case, a bridge of several interfaces.

• Andrwe Lord Weber provides a script that downloads EasyList rules and stunts privoxy with them.
• Wizardry and Steamworks offers a domain file that can be used as a forbidden file for polipo - turns out, polipo performs faster ad-blocking.