FortiGate 120G

The FortiGate 120G is a next-generation firewall positioned in a 1U rack form factor for mid-sized branches and headquarters, accelerated by the Secure SD-WAN ASIC SP5. According to the official data sheet, IPv4 firewall throughput is 39 / 39 / 28 Gbps with 1518 / 512 / 64 byte UDP packets, IPS throughput is 5.3 Gbps, Threat Protection throughput is 2.8 Gbps and IPsec VPN throughput is 35 Gbps. The appliance processes 42 million packets per second and its 64 byte latency is 3.17 µs.

In this class, the decisive factor for security is not raw speed but signature currency. In the CyberRatings.org November 2025 round, the FortiGate-200G scored 79.24% security effectiveness in the first measurement, while in the retest performed with the new IPS package Fortinet released within days that figure rose to 99.24% and the product earned a "Recommended" rating (CyberRatings.org, 2025). The FortiGate 120G's 5.3 Gbps IPS and 3 Gbps SSL inspection capacity provides the headroom needed to keep current signature sets permanently enabled.

What size of organization is the FortiGate 120G suited to?

The 120G is sized for a headquarters with 200-300 users or a busy regional branch. The appliance holds 3 million concurrent TCP sessions, opens 140,000 new sessions per second and supports 10,000 firewall policies and 10 VDOMs. In SSL inspection it handles 315,000 concurrent inspected sessions and 2,100 new connections per second. The built-in controller scales to 128 FortiAPs (64 of them in tunnel mode) and 48 FortiSwitches. It comes in a 1U rack form factor (5.52 kg, 49 dBA), operates with front-to-back airflow and draws only 38 W on average.

Where does the 120G make a difference compared with the FortiGate 100F?

The gap is on the order of 2x to 3x on almost every row, while average power consumption rises by only 3 W. The single step backwards is the copper port count: against the 22 GE RJ45 ports of the FortiGate 100F, the 120G offers 18 ports — but in return the number of GE SFP slots goes from four to eight. In deployments that require copper density, the missing ports are covered by a FortiSwitch managed over FortiLink.

How are the four 10GE SFP+ FortiLink slots used?

The data sheet assigns these four slots to the FortiLink role by default; in other words, their primary use is FortiSwitch connectivity. The FortiLink protocol turns the switch into a logical extension of the firewall and brings VLAN, port and PoE management into a single interface. These slots can be reconfigured as regular ports when needed, making a 10 Gigabit backbone connection or a dual-circuit redundant uplink design possible. Support for 48 FortiSwitches requires FortiOS 7.6.1 or later; earlier releases are limited to 32 switches.

When should you move up to the next model?

There is a detail here that deserves attention: the firewall throughput of the FortiGate 200F, at 27 / 27 / 11 Gbps, is below that of the 120G, yet it pulls ahead on Threat Protection (3 Gbps), SSL inspection (4 Gbps) and especially on new sessions per second at 280,000. In other words, the decision to move up should not be made on "higher firewall Gbps" but on which metric is under pressure. If inspection intensity and session setup rate are the bottleneck, the 200F is the right choice; if raw forwarding and VPN capacity take priority, the 120G is. For smaller locations, the desktop FortiGate 90G offers threat prevention close to the same class.

Which FortiOS version is required?

The 120G runs on current FortiOS branches; some features, such as support for 48 FortiSwitches, require 7.6.1 or later. With bulletin CSB-260330-1, Fortinet extended end of support for FortiOS 7.4 to 11 November 2028 and for 7.6 to 25 January 2030 (Fortinet Community, 2026). FortiOS 8.0, announced on 10 March 2026, brings shadow AI detection, AI-aware application control, OCR-enabled data loss prevention and post-quantum cryptography certificates (Fortinet, 2026). The data sheet does not state which version the performance figures were measured on.

As a Fortinet authorized channel partner, Sora Yazılım provides licensing, deployment, migration from the 100F and managed services across the entire FortiGate product family. We can establish together whether the FortiGate 120G is the right size for you, based on your user count, inspection policy, FortiSwitch/FortiAP inventory and VPN topology. Write to us through our contact page for a configuration recommendation and a quote.