Squid 3 is only listening only on IPv6

After upgrading to Ubuntu 13.10 from 12.04, I found that after installing Squid3 and copying my old squid.conf, that Squid was only listening on IPv6.  As I don’t have IPv6 Internet connectivity, this was an issue.

You can check what Squid is listening on by performing a netstat and then grep for squid3:

sudo netstat -antp | grep squid3

The result below show Squid is only listening on IPv6

tcp6 0 0 :::3128 :::* LISTEN 1140/squid3

To fix this I have modified the Squid.conf to listen on IPv4 addresses only.  This can be done as follows:

sudo nano /etc/squid3/squid.conf

Find the following entry (you can search with a Crtl+W)

http_port 3128

And change this to the following, which will listen on all IPv4 addresses:

http_port 0.0.0.0:3128

You can test again with a netstat:

sudo netstat -antp | grep squid3

As you can see, Squid is now listening on IPv4:

tcp        0      0 0.0.0.0:3128            0.0.0.0:*               LISTEN      29991/squid3