Internet Sharing from Mac OS VM (to Mac host or another Mac OS VM) - how to?

[tk-vm]

I would like to use Mac OS Internet Sharing to share internet from one Mac OS VM either to another Mac OS VM and/or to the host. For this scenario, I do NOT want to use the host internet connection. More specifically I have:

1) Snow Leopard VM with a legacy USB wifi card with extended range capability. I have this working in Snow Leopard VM. (The wifi card's drivers support only very old versions of Mac OS X.)

2) VMWare Fusion 12 with Catalina for Host OS.

3) A second VM for Mojave 10.14.6

I would like to make either or both of the host and/or the Mojave VM access Internet through Snow Leopard.

I have done the following already:

a) Set both VMs to use Network Adapter "Private to my Mac" setting.

b) Turned on the Apple Internet Sharing feature in "System Preferences->Sharing" in the Snow Leopard VM to share Internet from the USB wifi device to the (simulated) Ethernet adapter.

c) I don't know how to add the private network adapter to my host os network settings, so I went on to try to make the Mojave VM use the shared internet instead.

d) In Mojave VM set Network settings for (simulated) Ethernet adapter as follows:

Manual IPV4 address: 172.16.237.129 (the same one that VMWare provided dynamically)

Subnet Mask: 255.255.255.0

Router: 172.16.237.128 (this is the Snow Leopard IP address that is supposed to share its Internet.

DNS Server: 172.16.237.128

I find this does not provide Internet even though I can ping 172.16.237.128.

What other steps do I need to take...either/or...but not both at once to....?

a) make the Mojave use the Internet sharing from the Snow Leopard

b) make the host use the Internet sharing from the Snow Leopard

Thanks

[tk-vm]

The main issue, is how do I redirect the network activity (of either the host or the Mojave VM) to go through the Snow Leopard guest OS Internet connection?

[Mikero]

How would you accomplish this with physical devices?

[tk-vm]

> How would you accomplish this with physical devices?

Like this

https://www.macworld.com/article/352173/how-to-share-a-wi-fi-connection-on-one-mac-over-ethernet-to-...

Only in this scenario, the machine that needs to share its Internet is a VM and I would like either the host or another VM to be able to use the shared Internet. The vmnet8 and/or vmnet1 interfaces need to take the role of the Ethernet cable in the physical sharing described in the linked article.

[ColoradoMarmot]

So, you'd have to have a hardware device shared to the guest itself, and then that device connected to the internet?  Then have the host route through the guest?

I guess first, why would you want to do that?

Second, if you do, then rather than trying to do it with internet sharing (which is flaky to begin with), installing a VPN server in the guest and then install a VPN client on the host would probably be a lot more reliable.

But I'm not sure if/how you can have a network stack to the host with the host then looping back to the guest.  Seems like you'll hit a recursive problem at some point.

[tk-vm]

>So, you'd have to have a hardware device shared to the guest itself

The hardware device is plugged into the USB of the guest and run by the drivers installed into that same guest; it is not shared from the host to the guest.

>and then that device connected to the internet?  

Yes

>Then have the host route through the guest?

Yes, to get Internet from the Guest's connection.

>I guess first, why would you want to do that?

In my original post I stated "I have....1) Snow Leopard VM with a legacy USB wifi card with extended range capability. I have this working in Snow Leopard VM. (The wifi card's drivers support only very old versions of Mac OS X.)"

>Second, if you do, then rather than trying to do it with internet sharing

>(which is flaky to begin with), installing a VPN server in the guest and

>then install a VPN client on the host would probably be a lot more reliable.

I am open to consider this idea. How would I do it this way? Keep in mind, I would need the VPN server software to be for Snow Leopard.

>But I'm not sure if/how you can have a network stack to the host with the host

>then looping back to the guest.  Seems like you'll hit a recursive problem at some point.

Nothing is intended to be circular or recursive. The intent is that the Guest Snow Leopard gets Internet from the USB device, and either the host or another VM connects to that Guest Snow Leopard to use its Internet (not both at the same time). I do not need the Guest Snow Leopard to access anything on the host or on the other Guest.

[ColoradoMarmot]

It's probably time to upgrade the hardware to a modern version.  Snow Leopard shouldn't be on a network at all these days - it's a huge security risk.

I doubt that you'll ever get the host working.  For another guest, I still think that a VPN is likely your best option - internet sharing has always been flaky, and the older you get, the worse it was.  Plus trying to get it working across versions that old is going to be a challenge.

[Technogeezer]

Off the top of my head this problem sounds like the network routing tables on the host need to be inspected. The default route should lead to the Snow Leopard VM. 

I too question the practicality of the solution. The VM has to be running for network connectivity at the host. I would be concerned about implications of network interruption on the host should the VM need to be stopped - system level or fusion updates would have to be checked out. And network throughput would have to be tested to see if it w meets needs. . 

A cheap Intel NUC or Raspberry Pi running Linux seems like a much more practical solution