- You have a computer that is running Windows 8.1.
- The computer is using a forwarding IP address, or the Weak Host model is enabled.
- You run an application that requires a network socket connection to services that are running on the same computer or on a different computer.
In this scenario, the application may not establish a connection to its required destination services.
Hotfix informationA supported hotfix is available from Microsoft Support. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing the problem described in this article. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.
If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.
Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, go to the following Microsoft website: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.
PrerequisitesTo apply this hotfix, you must have Windows 8.1 installed.
Restart requirementYou do not have to restart the computer after you apply this hotfix.
Hotfix replacement informationThis hotfix does not replace any previously released hotfix.
After the TCP/IP driver incorrectly selects the loopback IP address, the address is cached in the TCP/IP destination path cache. The TCP/IP stack continues to select the loopback address for all successive network connections. This causes these connections to be unsuccessful. A destination cache dump file may show the loopback address as being selected (Source field) for a destination on a non-loopback or physical interface. To perform a destination cache dump file, run the following command:
The scenarios in which this problem may occur are as follows:
- The computer uses a forwarding IP address or has the Weak Host (send/receive) model enabled and temporarily sets the SkipAsSource field on a physical interface.
- The computer uses a forwarding IP address or has the Weak Host (send/receive) model enabled. Under certain network stress conditions, a race condition may occur in the TCP/IP path computation.
- The computer uses a forwarding IP address, has the Weak Host (send/receive) model enabled, or has an additional IP address assigned on the loopback interface. In this case, the TCP/IP stack may incorrectly mark a computed path as unconstrained. This leads to address lookup failures. It is a race condition and may occur when the IP address is temporarily disabled and then re-enabled.
Article ID: 2920546 - Last Review: 12 Feb 2014 - Revision: 1