Bridge Mode for en0 (Ethernet) no longer works after upgrade to Monterey

[to_rob2]

I ran into a strange problem after upgrading an Intel based Mac from Big Sur to Monterey 12.6.5 recently. I'm using VMware Fusion Player 13.0.2 with a Windows 7 guest. Before the upgrade, my network connection to the host used Bridge Mode and everything was fine. After the upgrade, the virtual machine cannot send any network packets anymore to any other machine when I'm using Automatic or Ethernet. When I select the WiFi interface (en1) for Bridge Mode, everything is fine, but much slower as with Ethernet (en0). Network Address Translation (NAT) is working, too.

The weird thing is that while I'm using Ethernet in Bridge Mode, the client (setup with DHCP) gets an IPv4 and IPv6 address, DNS servers and gateway address assigned from my router. I'm also able to ping these IP addresses from other machines in the same network. Only the client cannot ping any other machine, neither in the local network nor on the Internet.

I ran Wireshark to see what is going on. My client has 10.0.0.7, my router has 10.0.0.1. When I ping 10.0.0.1 from inside the client, Wireshark records no packets going out. It looks like as if the client not even tries to send a packet. But from time to time, I can see packets from 10.0.0.7 to 10.0.0.255 (broadcast address). When I ping 10.0.0.7 from another computer, I can see the ICMP packets reaching the client and also the response. Using ifconfig on the host machine, I can see that either en0 or en1 is part of bridge102, depending on the Network Adapter configuration for Ethernet (en0) or WiFi (en1). With WiFi selected, I see the outgoing packets and the response packets.

This is what I've tried so far to fix this issue: I restarted the host machine, I reinstalled VMware Fusion and I reinstalled the VMware Tools inside the client. I even completely disabled the firewall in Windows 7. Nothing helped.

I ran out of ideas. It looks to me that this is a bug in VMware Fusion on Monterey because VMware Fusion Player 13.0.2 on Big Sur worked perfectly. I cannot explain why the client can discover the DHCP server, send out IP lease requests and get a response from the router, but after that, I cannot even ping the router anymore. But as Wireshark does not detect any outgoing packets to the Ethernet interface, it's clear why there is no further response. I'm using NAT now, but I'm not happy with that as it breaks my firewall configuration distinguishing the various hosts in my network.

[Technogeezer]

Do you have a network topology diagram/description of how these networks are set up on your host Mac? 

[to_rob2]

It's quite simple: the network is a 10.0.0.0/24 class-c net with 10.0.0.1 being the firewall/router connected to the Internet. All the other hosts get their IP addresses via DHCP or use static IP settings. Nothing really special here. The virtual machine client should be bridged to this network as if it was a standalone machine with its own address 10.0.0.7. Usually, selecting Bridge Mode for the virtual network adapter (I'm using vmxnet3 as virtual device, BTW) should be enough and it worked this way up to Big Sur.

Then I upgraded the Mac to Monterey and found out that my additional ethernet adapter (bsdname en11) with an Intel i225-V3 chipset didn't work anymore. I removed this ethernet adapter and reactivated the old one (en0). Nothing else has changed besides the fixes that I tried and described in my first post.

[Technogeezer]

I assume that you turned off the wireless before switching to the Ethernet connection on the host Mac?

[to_rob2]

I tried it with and without disabling WiFi first and then switching to Ethernet. I also tried it with WiFi disabled or enabled afterwards. No improvement at all. By using ifconfig, I can see that bridge102 uses en0 as a member when I select Ethernet and en1 when I select WiFi. I have never seen both as a member of this bridge at the same time. Here's an example with en0:

bridge102: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
         options=3<RXCSUM,TXCSUM>
         ether 02:0a:cd:50:27:66 
         Configuration:
                 id 0:0:0:0:0:0 priority 0 hellotime 0 fwddelay 0
                 maxage 0 holdcnt 0 proto stp maxaddr 100 timeout 1200
                 root id 0:0:0:0:0:0 priority 0 ifcost 0 port 0
                 ipfilter disabled flags 0x0
         member: en0 flags=3<LEARNING,DISCOVER>
                 ifmaxaddr 0 port 6 priority 0 path cost 0
         member: vmenet3 flags=3<LEARNING,DISCOVER>
                 ifmaxaddr 0 port 20 priority 0 path cost 0
         media: autoselect
         status: active

 When I select WiFi,

member: en0 flags=3<LEARNING,DISCOVER>

changes to

member: en1 flags=8003<LEARNING,DISCOVER,MACNAT>

 The MACNAT flag is the only difference.

[Technogeezer]

Interesting. I'm trying to see if I can reproduce this.

I just switched my Mac Mini 2014 running Monterey 12.6.5 and Fusion 13.0.2 from wifi to Ethernet (first I disabled the wifi on the Mac through the Network pref panel, not just turned it off). I have a OpenSUSE Tumbleweed VM set up for bridged networking (to the Automatic) setting. 

The ifconfig on my system says:

bridge102: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
 options=3<RXCSUM,TXCSUM>
 ether 3a:c9:86:83:89:66 
 Configuration:
 id 0:0:0:0:0:0 priority 0 hellotime 0 fwddelay 0
 maxage 0 holdcnt 0 proto stp maxaddr 100 timeout 1200
 root id 0:0:0:0:0:0 priority 0 ifcost 0 port 0
 ipfilter disabled flags 0x0
 member: en0 flags=3<LEARNING,DISCOVER>
         ifmaxaddr 0 port 4 priority 0 path cost 0
 member: vmenet3 flags=3<LEARNING,DISCOVER>
         ifmaxaddr 0 port 20 priority 0 path cost 0
 media: autoselect
 status: active

Bridged networking is working fine to Ethernet for me with this configuration. 

By "Selecting WiFi" or "Selecting Ethernet" do you mean that you are selecting them under the Bridged Networking in the Settings for the network adapter?

If so, is Wi-Fi green or blank (like I have in my example).

[to_rob2]

Yes, that's what I mean with selecting which interface and mode the virtual network adapter is using. WiFi is red when I disable WiFi, otherwise it's green, but not grey.

[gringley]

So what Intel Mac are you running that would be able to use an Intel i225-V3 card?  

[to_rob2]

It was an USB Ethernet Adapter.