Firewall
In short
A firewall is the filter between your network and everything outside it. Rules decide which connections get through and which are dropped. Modern devices look beyond addresses and ports and recognise which application sits behind a connection. What they cannot do is stop an action that comes from inside and looks permitted.
What it sees, and what it does not
A firewall inspects traffic that passes through it. Traffic moving from one device to another inside the network often never crosses it at all. And encrypted traffic is a sealed envelope unless it is explicitly opened — which raises questions of its own.
Hence the practical limit: the common way into a small business is not through the firewall but through a login. A stolen credential looks like legitimate traffic to it, because technically that is what it is.
The mistake we see most
Treating the device as the finished job. A firewall is not a purchase, it is a rule set — and rule sets grow. After three years almost every configuration carries a rule that was opened «for a test» and never withdrawn.
The second mistake concerns home working. Once devices operate away from the office, the firewall at the premises no longer protects them. Protection then has to travel with the device rather than sit at the location.
The Swiss legal frame
The FADP does not require a firewall. It requires personal data to be protected by appropriate technical and organisational measures (Art. 8 FADP, SR 235.1) — and what counts as appropriate follows from the risk and the state of the art.
In practice: a box on its own does not discharge the duty, whereas a documented rule review goes some way towards it. What counts is that the decision can be traced, not the brand in the rack.
How we handle it
We review rule sets on a fixed schedule and record, for each opening, why it exists and who owns it — otherwise nobody later dares remove it. Operation and monitoring: IT security.
The most revealing question when taking over an estate: what is this one rule for? When nobody knows, the answer is usually «nothing, any more».
Related terms
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