This network employs a technology called captive portal which allows the administrator(s) to restrict network access to trusted users. In order to prevent certificate security warnings when accessing this portal, the network's filtering unit must issue to your computer or mobile device a file called an SSL certificate.
This guide will help you install the SSL filtering certificate for browsers based on the Mozilla platform, such as Firefox.
First, click the Download Certificate button below; this will download the certificate file to a temporary location on your computer.
Next, a dialogue will appear indicating that you have been asked to trust a new Certificate Authority. In this window, make sure that Trust this CA to identify web sites is checked, and then click OK.
(Note: This image shows Firefox on OS X 10.12. If your computer runs Windows or Linux, or another version of OS X, the layout and buttons may be different — but the general wording should be the same.)
You're done! You may continue browsing as usual; in most cases, you will not notice anything different after the certificate is installed.