(for addr in {1..254}; do for port in {20..23} 80; do nc -nvzw 1 10.25.0.$addr $port 2>&1; done& done) | grep ‘open’

I got to the understanding of for the address in 1 through 254 use port 80 of (port20 to 23), then netcat of 1.10.25.0…

I lack understanding after port 80, could you please help me out?

thank you in a million

When I try to do it via hostname or outward Ip address it fails returning:

This is nc from the netcat-openbsd package. An alternative nc is available
in the netcat-traditional package.
usage: nc [-46DdhklnrStUuvzC] [-i interval] [-P proxy_username] [-p source_port]
	  [-s source_ip_address] [-T ToS] [-w timeout] [-X proxy_protocol]
	  [-x proxy_address[:port]] [hostname] [port[s]]

If I have a server that is set up in pass-through (machine 1; not used in loop) is there a way to make this nc business work for me using machine 2 and machine 3 that are not in passthrough?
(*passthrough is at&t’s nomenclature for demilitarized I think).

I’ve already port forwarded a port to designate that machine 2 will host but still I cannot get machine 3 to connect…..arrrrggghhhh!!!! (now I can’t even get me to talk to me)