While using the session management with ASP.NET state service, if you add the setting <httpRuntime enableVersionHeader ="false"/> to the state server web.config (master web.config) to hide the "X-AspNet-Version: 2.0.50727" header you receive the error
"HttpException (0x80004005): Unable to use session state server because this version of ASP.NET requires session state server version 2.0 or above."
This exception occurs the very first time the session cache is used after the application is published to the server, or after IIS is restarted, or after the application pool recycles. Subsequent uses of the session cache after the first exception is thrown do not result in an error. The session cache continues to work properly until the next application re-publish, IIS restart, or application pool recycle.
The "X-AspNet-Version: 2.0.50727" header is sent by the state service to IIS. When sending the response back to the web application the state server should be including this header.
If we add the setting <httpRuntime enableVersionHeader ="false"/> to the state server web.config (master web.config), this header will not be sent from the state server to IIS and hence it throws the exception noted above.
Add <httpRuntime enableVersionHeader ="true"/> to the master web.config. The master web.config is found at C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\CONFIG\web.config or C:\WINDOWS\Microsoft.NET\Framework64\v2.0.50727\CONFIG\web.config depending on the bitness.
Add <httpRuntime enableVersionHeader ="false"/> to local web.config of the application.
Note :- Make sure you restart the state service after the configuration changes.
Since the "X-AspNet-Version: 2.0.50727" header is sent by the state server, setting <httpRuntime enableVersionHeader ="true"/> on the master web.config will ensure that the state server is sending the header to IIS. When <httpRuntime enableVersionHeader ="false"/> is set at the application level web.config, IIS will not send the header to the browser and you will not be able to see the "X-AspNet-Version: 2.0.50727" header in a network trace.
A better way to monitor the network traffic is to set just <httpRuntime enableVersionHeader ="true"/> in the master web.config and then you will see in a network trace the below snippet with the frame details being sent from the state server to IIS by ASPNET.
00 15 5D F4 C0 6D 00 15 5D F1 3E 65 08 00 45 00 00 7A 79 D2 40 00 80 06 00 00 AC 16 F2 11 AC 16 F2 2F A5 B8 12 E4 2E 55 75 CA 57 D4 A3 18 50 18 FF 15 3C DB 00 00 32 30 30 20 4F 4B 0D 0A 58 2D 41 73 70 4E 65 74 2D 56 65 72 73 69 6F 6E 3A 20 32 2E 30 2E 35 30 37 32 37 0D 0A 43 61 63 68 65 2D 43 6F 6E 74 72 6F 6C 3A 20 70 72 69 76 61 74 65 0D 0A 43 6F 6E 74 65 6E 74 2D 4C 65 6E 67 74 68 3A 20 30 0D 0A 0D 0A