Delay between GotRequestHeaders and ClientDoneRequest

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Paolo asked on 08 Feb 2023, 09:56 AM

Hi i'm using fiddler classic to analize performace of a client/server application (client winform and server on Azure .Net 4.8).

Comparing fiddler trace on 2 different PC (home pc and work pc) i notice a very long delay beetween GotRequestHeaders and ClientDoneRequest on work pc.

For example:

Home PC (equal time):

GotRequestHeaders 21:39:55.294
ClientDoneRequest 21:39:55.294


Work PC (0.4 difference):

GotRequestHeaders:    12:46:54.730
ClientDoneRequest:    12:46:55.109


Do you have any idea what could be causing this problem?
Could be an antivirus/Firewall/some software?




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Nick Iliev
Telerik team
answered on 08 Feb 2023, 11:53 AM

Hello Paolo,


The GotRequestHeaders is the timestamp for when Fiddler finishes reading the HTTP request headers from the client. The ClientDoneRequest is the timestamp for when Fiddler sends the HTTP request body to the server.

One possibility for such a delay between both times could be reading large files, but given that you are observing that an identical request is acting differently on different hosts, that indicates that the work PC host processes the request body differently. It could be that the client app has performance degradation on your work PC (at least compared to tour home PC), which causes the body message to proceed slowly.

If your client application (that issues the request) is a browser, you could try to change the testing browser. You can also try to exclude (if that is possible from a security point of view) any software that might cause performance degradation like antivirus, firewall, other proxies chained to Fiddler, VPN tooling, etc.


Nick Iliev
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