SMB Multichannel Issue: Multichannel Capability Not Recognized by Windows 11 Client

Question

Hi Support Team,

I have successfully set up SMB Multichannel on a Synology DSM v7.1 server. The configuration works as expected on one Windows 11 Pro machine, but I'm unable to get it working on another Windows 11 Family edition machine.

Environment Details:

• Server: Synology DSM v7.1
• Client 1 (Working): Windows 11 Pro
• Client 2 (Not Working): Windows 11 Family
• Network Setup: Two Ethernet adapters on the client, both properly configured for SMB Multichannel.

Steps Taken (mostly fro

1. Verified SMB Multichannel is enabled on the server and client (Get-SmbClientConfiguration confirms this).
2. Ensured both Ethernet adapters:
   • Are enabled for ms_msclient.
     • Appear in Get-SmbClientNetworkInterface.
     1. Confirmed:
        • SMB Dialect: 3.1.1 reported by Get-SmbConnection.
          • NetworkCategory: Private (tried both with and without IPv6).
3. Followed all SMB Multichannel troubleshooting steps in the Microsoft documentation.

More Details:

• Running Wireshark shows no FSCTL_QUERY_NETWORK_INTERFACE_INFO requests from the client.
• In the Negotiate Protocol Response from the server:
  • MULTI_CHANNEL capability is set to 1.
  • However, in the Session Setup Request, the client reports MULTI_CHANNEL as 0.

Questions:

1. What could cause the client to disable MULTI_CHANNEL despite it being advertised by the server?
2. Are there specific differences between Windows 11 Pro and Family that might impact SMB Multichannel functionality?
3. Is there any additional troubleshooting or registry configuration I should attempt to force SMB Multichannel functionality?

Any assistance or insights would be greatly appreciated!

Thank you for your time and support.

Answer 1

Hello

Thank you for posting in Q&A forum.

Here are the answers for your references.

1. Possible Causes for Client Disabling MULTI_CHANNEL:

Network Interface Issues, Firewall Settings, SMB Version, Network Profile

2. Differences Between Windows 11 Pro and Family:

• Feature Support: Windows 11 Pro includes additional networking features and support for advanced configurations like SMB Direct, which might not be available in the Family edition

• Security and Management Tools: Pro versions have more robust security and management tools that can impact network configurations and performance

3. Additional Troubleshooting and Registry Configuration:

• Update Network Drivers: Ensure that all network drivers are up to date on the Windows 11 Family machine

• Registry Tweaks: You can try adjusting SMB Multichannel settings via the registry. Use the following PowerShell commands to enable and configure SMB Multichannel:

Set-SmbClientConfiguration -EnableMultiChannel $true

• Network Adapter Settings: Check and configure the network adapters to ensure they support Receive Side Scaling (RSS) and are not limited by power-saving features.

• Packet Capture: Perform a packet capture to analyze the SMB negotiation process and identify any issues with the MULTI_CHANNEL negotiation.

References:

[1] SMB multichannel troubleshooting - Windows Server | Microsoft Learn

[2] Windows 11 Home vs. Pro: What's the difference?

I hope the information above is helpful.

If you have any questions or concerns, please feel free to let us know.

Best Regards,

Daisy Zhou

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Answer 2

Thanks for your reply.

Actually after a lot of testing, I realized that it is working but only when connecting the share to a drive letter from a shell prompt

ie this works:

net use S: \\192.168.1.100\Share /user:guest -> Get-SmbMultichannelConnection reports multiple IPs

But opening using the url in the explorer URL \192.168.1.199\Share does not work.

Is there any reason why?