A firewall spec sheet leads with a big throughput number. The number that matters is the smaller one — throughput with intrusion prevention, antivirus and filtering switched on, which is how you will actually run it.
The number that matters
Inspection costs performance. An appliance rated for several gigabits of raw throughput may deliver a fraction of that with full UTM enabled. Size on the inspected figure, or you buy a firewall that quietly throttles the office once security is turned on.
“An under-sized firewall does not fail loudly. It just makes the internet feel slow, and nobody connects the two.”
Sizing for growth
Capacity is about more than headcount. VPN tunnels, additional sites, guest Wi-Fi and cloud-heavy workloads all add load. Size for where you will be in two years, with room to enable more inspection as threats evolve.
Headroom is cheaper than a swap
Buying a size up front is almost always cheaper than replacing an appliance that ran out of room — and it lets you turn on new protections without a hardware project.
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