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SMB Multichannel skips non-routable IP addresses of a network interface if routable IP addresses are also configured
Article ID: 2777646 - View products that this article applies to.
On a Windows Server 2012-based computer or a Windows 8-based computer that connects to a server message block (SMB) 3.0 file share, SMB Multichannel ignores non-routable IP addresses if the network interface has both routable and non-routable IP addresses configured. This behavior occurs even though SMB Multichannel typically tries to connect with additional interfaces if multiple network interfaces exist, and tries to establish multiple TCP/IP connections for a Receive-Side Scaling (RSS) capable network interface.
Note Non-routable IP addresses include IPv6 link-local addresses and Automatic Private IP Addressing (APIPA) IPv4 addresses.
Consider the following example scenario:
This behavior is by design. SMB Multichannel uses non-routable IP addresses for a network interface only if no routable IP addresses are available for the interface. If a network interface has both non-routable and routable IP addresses configured, SMB Multichannel ignores the non-routable IP addresses.
In the example scenario, only one network interface (interface A) is used for the SMB session because the link-local addresses of the other interfaces are ignored by SMB Multichannel, and the client can connect only to the link-local address of the server. Additionally, only one TCP/IP connection is created for interface A because the link-local address of A is ignored by SMB Multichannel, and the client can connect only to the link-local address of the server.
To work around this behavior, use one of the following methods to enable multiple connections for a network interface:
For more information about SMB Multichannel, go to the following Microsoft Server and Management Blog article:
The basics of SMB Multichannel, a feature of Windows Server 2012 and SMB 3.0APIPA IPv4 addresses use the 169.254.0.0/16 prefix. IPv6 link-local addresses use the FE80:: /64 prefix. For more information about APIPA IPv4 and IPv6 link-local addresses, go to the following Windows Server website:
Unicast IPv6 addressesFor more information about how SMB clients select network interfaces, go to the following MSDN website:
SMB tech document - Appendix A: Product Behavior
Article ID: 2777646 - Last Review: January 3, 2013 - Revision: 2.0