Billion BIGUARD S20. Supported network protocols: PPPoE, DHCP, NAT, DMZ, SNTP, SNMP. Security algorithms supported: SSH. Dimensions (WxDxH): 390 x 210 x 44 mm. Operating temperature range (T-T): 0 - 40 °C, Storage temperature range (T-T): -20 - 70 °C. Compatible operating systems: Microsoft Windows, Linux, Macintosh