# Network Loopback

| ## Network Loopback How it works: This screen allows you to start a network loopback task allowing you to use a packet generator to send packets and then receive them. The loopback will look for the Protocol selected on the Rx Port specified. All packets received on that port will be re-sent to Destination IP and Port specified.

Select your options then press Start to run the loopback
Protocol | UDP TCP | Protocol to test
Rx Port |  | Port EVM should receive the packets on
Destination Port |  | Destination Port EVM sends the packet to
Destination IP |  | Destination IP EVM sends the packet to, in dot notation. E.g. 192.168.2.102
Use Static Route |  | If your packet generator does not respond to ARPs then check this. If checked, you must supply a MAC address below.
Destination MAC |  | This field is only needed if you are using a static route. It is the MAC address associated with the Destination IP. Static routes should be used with line rate protocol testers like smart bits.