I have an Allied Telesyn 10/100Mbps Fast Ethernet Switch. Plugged in is the main line to port one, direct from my Comcast router, an IBM ThinkCentre 8143-28U to port two, an Xbox 360 "classic" (mfr date 2009) in port three, and a custom built with a Gigabyte Z77-DH3 board into port four. Now, the fun part is as such. When my computer, the custom build, is off, no devices plugged into the switch will receive network data, and furthermore are not recognized by the router as even being connected, though they can communicate within the local switch ecosystem.
Thoughts on how to eliminate such a problem?