CaptureNet

1、From Settings->Action (first panel which appear) choose Flush buffer to file , Overwrite, and be sure that a capture file name is entered. 



2、From Settings->Miscellaneous choose a pachet buffer size (no. of packets) adequated to your network traffic (a good value for a not quite overloaded network is 1000); 
(this step will require a program restart)




3、Uncheck Display capture (on the main panel) to reduce the CPU loading; Check Promiscuous (to capture all packets). 



4、Uncheck Use Filter or use a NULL filter (by clicking the Remove button). 
(very important)



5、Start capture (click button or press Ctrl-A)