Update vpn_softetherbridge.md : to briged interaface will assiged with physical interface's MAC address.

[LinearAlpha]

In previous methods, the physical and bridged interfaces were both online, so a single device had two different IP addresses. Thus, it caused performance issues and sometimes (in my case, all the time) DNS errors that prevented the device from accessing the Internet.

By setting the bridge interface with the physical interface's MAC address. We can take advantage of the bridged interface with a single IP address from the router and improve the performance of the VPN connection. Also, users do not need to search for a new IP address assigned to the bridge interface.

Please let me know if you have any concerns or questions about these changes. Thank you!

[sebastiankb]

from today's PlugFest call:

• there is no objection to use VPN during the PlugFest
• @egekorkan will test the provided updated guideline from @LinearAlpha (@k-toumura will support)
• PR can be merged when the merge error is solved

[TallTed]

@LinearAlpha @sebastiankb @egekorkan
Please correct typos in title, from

Update vpn_softetherbridge.md : to briged interaface will assiged with physical interface's MAC address

to

Update `vpn_softetherbridge.md`: bridged interface will be assigned with physical interface's MAC address

[k-toumura]

Thank you for the PR. I've tested it out on my end as well.

With Linux bridges, one of the NIC's MAC addresses is automatically assigned to the bridge itself, and the IP address is generally assigned only to the bridge. Is there a specific reason to explicitly copy the MAC address? For example, in a configuration like the one below, would it be necessary for br0's MAC address to always match the physical NIC (in this case, wlan0)?

graph TD;
  vpnbridge(SoftEther VPN bridge)
  dhclient(DHCP client and other processes)
  other(other machines in the local WiFi network)
  tap_svpn([tap_svpn<br>MAC: 01:23:45:67:89:ab])
  br0([br0<br>MAC: same as tap_svpn or wlan0<br>IP: 192.168.30.2])
  wlan0([wlan0<br>MAC: cd:ef:01:23:45:67])
  subgraph VPN Bridge
   tap_svpn --> vpnbridge;
  br0 --> tap_svpn;
  br0 --> wlan0;
  dhclient --> br0;
  end
  subgraph local WiFi network
  wlan0 --> other
  end

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On a separate note, by using ip link add br0 type bridge instead of brctl addbr br0, we could eliminate the need to install bridge-utils.

Thank you again!

[LinearAlpha]

@k-toumura

Hello, sorry for the late reply,

• Is there a specific reason to explicitly copy the MAC address?

In my experience, without copying the MAC address into the bridge interface, I had an issue with the DNS resolution, so the bridge or VPN server could not connect to the internet.

Also, I've seen that copying the MAC address into the bridged interface shows better performance and stable connections. (I've tried to figure out why it is more stable, but I cannot figure out why)

• would it be necessary for br0's MAC address to always match the physical NIC?

The MAC address always matches the physical interface that connects to the ethernet (more likely, the interface that connects to the router).

So, yes, in this case, it needs to match the MAC address br0 with wlan0.
However, most of my cases were using WLAN as a VPN wifi access point that I did not know how to configure it for this case, but my guess is similar to how to set up a wifi connection into netplan but having extra lines for bridged network.

Lastly, I used brctl, which can be a permanent solution that does not need to reconfigure every time it reboots.

Thank you for your time!