X-ServerSocket Multiple Server Sockets?

[Peter]

I've been running into some unexpected and strangely consistent HTTP/1.1 504 Fiddler - Receive Failure, and when looking into the response I see a the X-ServerSocket value to be two values: 

X-SERVERSOCKET: REUSE ServerPipe#1321REUSE ServerPipe#384*NEW*

This would seem to imply that the two server sockets were used for the connection, this seems bizarre. Are there conditions where this should happen?

[Eric Lawrence]

Hi, Peter--

The string "X-SERVERSOCKET: REUSE ServerPipe#1321REUSE ServerPipe#384*NEW*" means

"First we attempted to reuse the connection to the server established in session #1321. But that connection did not work (e.g. calling Send with the new request on the existing socket failed). So next we attempted to reuse the connection to the server established in session #384. But that connection didn't work either. So, having run out of available established sockets to reuse, we instead tried establishing a NEW connection to the server and using that connection."

If that third attempt fails, Fiddler doesn't retry another NEW connection; the error is fatal because only one NEW connection is permitted per request.

Regards,
Eric Lawrence
Telerik