Imagine this setup:

- internet - [pc1] - [pc2] - [pc3]

pc1, pc2, pc3 each have two network cards and run Windows 10. pc1 has Internet Connection Sharing enabled, so pc2 connects to the internet through it. How do I set up Internet Connection Sharing on pc2 as well, so pc3 gets connected to internet through pc2? Problem is that Windows 10 seems to use a hardcoded network ( for ICS. I suppose I would need to set up pc2 to use another network, to avoid IP conflicts. How do I do that?

  • 1
    Save yourself the trouble and get a switch. A 4-port 100 MBit/s switch is only a few bucks. – Daniel B Dec 10 '17 at 12:45
  • @DanielB Even better would be to plug the internet cable into a router with ethernet ports and hook up all 3 pcs, I know. But it's not an option. – Windows11 Dec 10 '17 at 13:33

Don't set up the second ICS instance at all. On PC 2, bridge both network cards so that the computer begins acting as an Ethernet switch. (You can do this in Windows' ncpa.cpl by selecting both ports and choosing "Bridge Connections" from the right-click menu.) That way devices on both "sides" will belong to the same subnet with no extra configuration.

(Of course it would be better to connect a real switch to PC 1, and chain both PC 2 and PC 3 directly off that.)

  • What would be the network setup on pc3 then? Just like on pc2? pc1 will be the default gateway after it gets an IP address from pc1? – Windows11 Dec 10 '17 at 13:32
  • Just regular DHCP. – grawity Dec 10 '17 at 14:09
  • Note: You might not need ICS at all if you already have another router with DHCP in front of PC1. In that case you could just use bridging on all computers. – grawity Dec 11 '17 at 0:02
  • first attempt to get an IP on pc3 after bridging the NICs on pc2 failed. I assume I might need to check firewall on pc2 and add explicit rules to allow DHCP traffic (UDP ports 67,68)? – Windows11 Dec 11 '17 at 19:04
  • Shouldn't be necessary with the normal Windows firewall. (Third-party ones? Maybe.) I'd first install Wireshark and investigate. When PC3 sends the DHCP query, does PC1 see it? (Does PC2 see it on both interfaces?) Likewise with responses. – grawity Dec 11 '17 at 19:21

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