Symantec Firewall/VPN Model 100 is a security appliance designed to provide both firewall and VPN functionality for small offices. It offers a web-based interface for easy management and allows for secure internet access and interaction between remote locations, business partners, and corporate networks. The appliance also includes a built-in 10/100 Mbps auto-sense switch, a DHCP server, and supports features like Dynamic DNS, PPPoE, and IPSec pass-through.