For PCs, PCMacLan is likely the best solution. It works with my Apple IIgs via a Shiva Fastpath 5 without a problem. I have also used DAVE to access Windows/SMB/CIFS file and printer shares under classic Mac OS.
The Apple II crowd came up with a pre-configured virtual machine (or Raspberry Pi) running netatalk 2.2.4 that supports net booting, with an obvious focus on the Apple IIgs. It should also be compatible with classic Macs. http://appleii.ivanx.com/a2server/
Personally I have always used Localtalk-to-Ethernet bridges when networking my classic Macs that lack Ethernet. It should be noted that the Shiva/Kinetics Fastpath series and the Cayman Systems GatorBox are the only two bridges that can properly route MacIP (TCP/IP over Localtalk) straight out of the box. The more commonly available Dayna adapters only route AppleTalk. If you have a Mac running the Localtalk Bridge Control Panel, I have heard rumors that running Open Transport on the machine allows it to route MacIP, otherwise there is IPNetRouter.
The Apple II crowd came up with a pre-configured virtual machine (or Raspberry Pi) running netatalk 2.2.4 that supports net booting, with an obvious focus on the Apple IIgs. It should also be compatible with classic Macs. http://appleii.ivanx.com/a2server/
Personally I have always used Localtalk-to-Ethernet bridges when networking my classic Macs that lack Ethernet. It should be noted that the Shiva/Kinetics Fastpath series and the Cayman Systems GatorBox are the only two bridges that can properly route MacIP (TCP/IP over Localtalk) straight out of the box. The more commonly available Dayna adapters only route AppleTalk. If you have a Mac running the Localtalk Bridge Control Panel, I have heard rumors that running Open Transport on the machine allows it to route MacIP, otherwise there is IPNetRouter.