This page will give you more insight about which hardware requirements are needed and why. You can built highly customized systems as IPFire scales from very small boards to huge machines depending on the workload you expect.
Processor Architecture
IPFire supports the x86_64 and ARM64 architectures. It is recommended to have at least 1 GHz clock speed. For x86_64, EFI and legacy BIOS systems are supported. For ARM64, systems that use EFI are supported as well as some Single Board Computers.
32-bit platforms are no longer supported.
Memory
The developers recommend at least 1GB. If various add-ons are used, the amount of memory should be even higher. Memory consuming features/add-ons are the web proxy and URL filter as well as the Intrusion Detection/Prevention System
Another ( temporarily ) memory consuming function is the upgrading. Download / decrypt are done in memory.
Mass storage
Mass storages devices typically have a lot of capacity. They could serve as media for backups or mass data storage with low access times. In IPFire different types of mass storage can be used.
Drives
Although the base system of IPFire requires only a couple of hundreds of megabytes for program data, the minimum amount of storage is 2GB. The developers recommend at least 4GB for log files and add-on packages.
IPFire supports drives of 3 TB and larger with IDE, SATA and SCSI. Most hardware RAID controllers are supported, too.
Networking
IPFire needs at least two network adapters (see Network topologies and access methods). The vast majority of Ethernet network adapters on the market works very well. Adapters with 10MBit/s and ISA connector are not supported any more. Also not all adapters with 10GBit/s are working.