• Configuration File • Logs • E-Mail • Network Diagnostics • Options • PC Database • Remote Admin • Routing • Security • Firmware Options Backup DNS Backup DNS (1) IP Address: . . . Backup DNS (2) IP Address: . . . These DNS (Domain Name Servers) are used only if the primary DNS is unavailable. UPnP Enable UPnP Services   Allow configuration changes through UPnP   Allow Internet access to be disabled MTU MTU (Maximum Transmission Unit): (1..1500) bytes This setting only affects PPPoE ,L2TP and PPTP connections.