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.