What is a Firewall?
Firewalls are a set of rules designed to prevent the unauthorized access to a private network.
Firewalls are frequently used to protect information shared on an intranet, which scans all messages moving in and out of the network and blocks those that do not abide by the established security criteria. They are also used to block attempts to gain unauthorized access to a computer by enforcing secure authentications certificates and logins.
Firewalls are usually considered a first line of defense in the protection of confidential information. Further lines of defense usually entail encryption via a VPN solution.