how can i do that?

How exactly do you want to use Dude in the network with proxy auth ?

it will be fine, to see somwhere in options of dude the place, where i can write ip of my network proxy server, and login+pass

you need to force dude send all you requests and probes over proxy to:
- monitor some internet servers, not accessable directly
or
- monitor your proxy server
or what?

need to force dude send all you requests and probes over proxy to:
- monitor some internet servers, not accessable directly