I have below A B C devices in a work LAN, but no permission of the office switch.
in the office LAN:
A.a router (I want to expand a physical net port and it's what I happen to have at hand)
B.friend's computer (which provides some file and web services inside the office)
in my router's LAN:
and maybe more mobile devices later
Is there a way for laptop C to access computer B ?
Computer B to laptop C is otherwise not important.
Similar questions must be asked somewhere but I'm poor at summerizing keywords... Any link or ref would be appreciated.