Welcome to this demo clip, Configuring Squid.
In this clip, you'll learn about the squid.conf file,
which is the file that Squid relies on for its configuration.
We'll take a look at some common Squid configuration options and get a
general understanding of how to configure Squid with a special emphasis
on the options that are focused on security.
Let's get started.
One of the advantages to using Squid is that it is very configurable.
If we navigate to the Squid configuration documentation page,
we can get a great breakdown of the different configuration
options or directives that are available to us.
Let's check out a few of these to get a general
understanding of how a squid.conf file is set up.
First, let's take a look at the cache_dir option.
Let's make sure we click on the version 5,
as it is the latest stable version which we are using.
When we click on this,
it brings up a very detailed documentation page on this directive.
It tells us things like required directives that this directive depends on,
the default value of this directive if we don't
supply it within the squid.conf file, and even a suggested config option.
Below this,
there's a very detailed piece of documentation that lets us know all
the different ways that we can use this directive.
Now, let's back up and take a quick look at some of the
more security‑focused options available.
First, let's take a look at the access control list, or ACL directive.
This directive is essentially used to allow access to the Squid
proxy cache content to selected IPs or ports by working in
combination with other access directives,
as you'll see in demos that follow this one.
This directive has a suggested configuration as shown here.
For example, this directive line, if put into a squid.conf file,
will create an access control list with the name localnet of type source,
which allows all IP addresses within this range.
Essentially, this grants your local network access to the Squid proxy cache.
Another directive that we should be aware of is this http access directive.
This is one of the most used directives in the squid.conf file.
It essentially grants different access control lists
access to the cache and denies others.
Here is the suggested configuration.
As you can see, here we are allowing members of the localnet access control list,
which we touched on a bit earlier, to access the cache.
Here, we are making sure to deny other unspecified users.
There are many, many directives available to us.
You can check out this site for a full listing.
For the rest of this course,
we'll make heavy use of the ACL directive along with a couple of others.
For a full listing of authentication options and relevant directives,
you can check out this piece of documentation here.
Please stick around for the next demos where we'll take an existing
squid.conf file and build on it by adding in some access control
lists and authentication directives so that we can configure Squid
such that we ensure access permissions and authorizations are managed
according to pr.ac‑four.