Soekris Engineering net4501

This compact, low-power, low-cost, advanced communication computer is based on a 133 Mhz 486 class processor. It has three 10/100 Mbit ethernet ports, up to 64 Mbyte SDRAM main memory and uses a CompactFlash module for program and data storage. It can be expanded using a MiniPCI type III board and a low-power standard PCI board.
It has been optimized for use as a Firewall and VPN Router, but has the flexibility to take on a whole range of different functions as a communication appliance. The board is designed for long life and low power.

Specifications:

100/133 Mhz AMD ElanSC520
16-64 Mbyte SDRAM, soldered on board
1 Mbit BIOS/BOOT Flash
CompactFLASH Type I/II socket, 8 Mbyte FLASH to 4 Gbyte Microdrive
1-3 10/100 Mbit Ethernet ports, RJ-45
1 Serial port, DB9. (optional 2nd serial port)
Power LED, Activity LED, Error LED
Mini-PCI type III socket. (t.ex for optional hardware encryption.)
PCI Slot, right angle 3.3V only. (t.ex for optional WAN board.)
8 bit general purpose I/O, 14 pins header
Hardware watchdog
Board size 4.85" x 5.7"
Power using external power supply is 6-20V DC, max 10 Watt
Option for 5V supply using internal connector
Operating temperature 0-60 °C

Software:

comBIOS for full headless operation over serial port
PXE boot rom for diskless booting
Designed for FreeBSD, NetBSD, OpenBSD and Linux
Runs most realtime operating systems