As mentioned earlier, Squid can also be used as a reverse proxy server. In this situation, Squid is caching content for one or more web servers, reducing the load on the servers. You can configure the reverse proxy server by navigating to Services | Squid Reverse Proxy. There are several tabs, but the default tab is General.

The first setting is the Reverse Proxy Interfaces list box, which allows you to select one or more interfaces to which the reverse proxy will bind. Since the reverse proxy will be serving content to remote users, you probably want to bind it to WAN (or possibly to multiple WAN-type interfaces). In the User Defined Reverse Proxy IPs, you can specify user-defined IPs to which Squid will bind. You also need to specify the external fully qualify domain name of the WAN IP address in the External FQDN edit box. You can use Squid as a reverse proxy for both HTTP traffic and HTTPS traffic, but you have to enable them separately; there are two separate checkboxes on the page: Enable HTTP Reverse Proxy and Enable HTTPS Reverse Proxy. You can also specify different HTTP and HTTPS ports than the defaults of 80 and 443.