General Computing
networking home-networking bridge
Updated Sat, 01 Oct 2022 05:07:37 GMT

Windows network bridge not working for guests


I recently bought a second Ethernet interface for my Windows 10 machine (TP-Link TG-3269 in particular, the first interface is the one built into my BIOSTAR TZ77B motherboard) in hopes of making a network bridge as follows (all Ethernet cables):

Router <=> Interface 1 <=> Interface 2 <=> Switch/other guests

Note that I'm not doing Router <=> Switch <=> Interface 1/other guests because Router <=> Interface 1 is gigabit, which I want to keep, while the switch is megabit.

I'm assuming that the network bridge makes the host act as a switch, i.e. DHCP, etc. managed by the router coming through Interface 1 should still be accessible to other guests via Interface 2. However, after following many guides and setting up the network bridge, the host works just fine (with a static IP) but all the guests I've tried can't communicate past Interface 2. For example, on an OS X guest, ifconfig shows the following (no IPv4 address):

en5: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
options=b<RXCSUM,TXCSUM,VLAN_HWTAGGING>
ether 00:00:ba:60:05:3e 
inet6 fe80::877:a12:183c:eec3%en5 prefixlen 64 secured scopeid 0x4 
nd6 options=201<PERFORMNUD,DAD>
media: autoselect (1000baseT <full-duplex,flow-control>)
status: active

Monitoring the guest's network interface with Wireshark, I only see a ridiculous amount of packets arriving from Interface 2, but they're all low-level. Every once in a while there are packets of other types but none of them result in the guest getting an IP address, let alone connect to the Internet. Something similar happens to a Raspberry Pi guest.

What am I missing? Following this answer, I have already enabled promiscuous mode on both interfaces, but it hasn't changed anything. I haven't really tried Internet Connection Sharing but I would prefer to leave all my devices under the same network, and I think ICS creates a different network by default.




Solution

The solution seemed to be manually installing the drivers for Interface 2, the ones Windows 10 had automatically installed weren't working properly. I installed mine from the installation CD, but as of writing they can also be downloaded here.







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