Glossary A–ZLetter F
Firewall
A firewall is a protective barrier between networks that uses rules to decide which connections are allowed through and which are not.
It can be a separate device, be built into the router or run as software on a computer.
As a rule, a player does not need to be reachable from the internet: it establishes its own outbound connections, fetches content and reports in. Incoming connections can therefore be blocked. In company networks, IT departments often allow only specific destinations, such as the addresses of the management software, the media storage and the time server. If one of them is missing, the player does not download or shows the wrong time.
Before the rollout, the provider should supply a complete list of the addresses and ports required; content from the web such as web pages, streams or weather brings its own destinations. Some company networks break open encrypted connections for inspection (TLS inspection), which can interfere with players that check certificates strictly. A firewall does not protect against everything: physical access to the device, weak passwords and outdated software remain separate tasks.