. D-Link Wireless N Unified Firewall Service Router D-Links DSR-250N Unified Services Router is a secure high performance networking solution to address the growing needs of small & medium businesses. Integrating Wireless N & USB (Universal Serial Bus) support the DSR-250N offers comparable performance to traditional wired networks but with fewer limitations. Optimal network security is provided via features such as virtual private network (VPN) tunnels IP Security (IPSec) Point-to- Point Tunneling Protocol (PPTP) Layer 2 Tunneling Protocol (L2TP) & Secure Sockets Layer (SSL) making it ideal for SMB & branch offices that need a secure reliable connection to remote resources..