We have some web systems that in the past have experienced HTTP 408 response codes when making a request. They can happen at any time, there doesn't seem to be any pattern to them.
The problem we have is that the client request goes through a TMG gateway, and IIS never logs the 408. The last request I see is a 200, and subsequently a client received a 408.
Do 408's make it to IIS logs, or are 408's higher up in the stack meaning the request never makes it to IIS?