Losing NAT network connectivity

[Technogeezer]

Fusion on Apple Silicon Tech Preview , Mac mini M1 (2020), macOS Monterey 12.1. Wifi networking.

From time to time with the Tech Preview, I'm losing connectivity to the "outside world" when using NAT networking. I find this happens most often when I'm creating and deleting virtual machines that use NAT networking.

The guests (Various Linux flavors and "that unsupported Microsoft operating system") all complain that a network connection is not established.

Simply stopping and restarting the guest does not return connectivity. Nor does disconnecting the network adapter and reconnecting it. I do find that the connectivity returns if I stop the VM, stop Fusion, then restart Fusion and the guest.  No other changes and presto! the NAT networking is working again.

Something's up with NAT networking. Since restarting Fusion is also restarting the Fusion networking daemons and config - so my guess is something's wonky there.  With all the problems people are seeing both here and in the released Fusion version on Intel Macs, it may not be isolated to my configuration.

@Mikero What info can I collect for VMware the next time this happens?

[fredvd]

I'm seeing the same behavior on OSX 12.4 with the last tech preview update from June.   Installed  an ubuntu 20.04 focal ,updated the mainilne kernel per the instructions found on this forum at https://communities.vmware.com/t5/Fusion-for-Apple-Silicon-Tech/How-to-install-Ubuntu-on-Fusion-Tech... .

When I start the VM networking is fine, allthough on login ubuntu complains that it couldn't connect to https://changelogs.ubuntu.com so networking seems to take a while before it is loaded.

I suspect it has something todo when my mac goes to sleep, when I keep using it the network stays up, when I come back after a few hours or the next morning, the network connectivity is gone.  I can still ping the gateway.

[fredvd]

I can confirm that the mac going to sleep is the cause or one of the causes of loosing network connectivity in a virtual machine when it it 'NAT'ted.  (Share my IP with my mac).   I disabled sleep on the Mac host before the weekend and a virtual machine with Ubuntu 20.04 arm has been running without any netowrk connectivity loss.

[Technogeezer]

It’s not just macOS sleeping that causes this behavior. I can be working with a VM and the NAT networking simply stops working all of a sudden. 

[fredvd]

" is the cause or one of the causes "

[VMware-Ben]

I'm seeing what may be the same issue on Player Version 12.2.3 (19436697) running on a Intel Mac.

I can consistently reproduce this when http3/quic is attempted in a single VM. Networking will stop working across all VMs (Both Ubuntu 22.04 and Windows 10 with all updates applied). It appears to break the gateway that Fusion is presenting as the output of route changes and arp shows incomplete to the gateway. The only fix is to shutdown all VMs and quit Fusion. 

[Technogeezer]

That's a very interesting observation (and nice to know I'm not seeing things that aren't really there). I've seen this behavior on both the "real" version of Fusion on an Intel Mac as well as the Tech Preview on a M1 Mac.

Could you share how you're executing the http3/quic request - I'd like to see if I can reproduce this at will as well.

[VMware-Ben]

I have some tools for monitoring network activity so I can see what's happening at the time. Many application use it so you may have others but I've noticed FireFox will consistently initiate a http3/quic connection on launch. As a test you can disable http3/quic by browsing to about:config and changing network.http.http3.enable from true (enabled) to false (disabled). I've not seen the issue since doing that but it returns immediately if I set it back to true.

[Julian_Lim]

Solution:

https://communities.vmware.com/t5/VMware-Workstation-Pro/VMWare-Workstation-Pro-15-NAT-drops-after-a...