Why does the user agent resubmit a request after server does a TCP reset?

Question

We\'ve recently noticed a problem where some user agents would repeat the same POST request without the user actually physically triggering it twice.

After further s

Answer 1

This is part of the HTTP 1.1 protocol to handle connections that are closed prematurely by servers.

http://www.w3.org/Protocols/rfc2616/rfc2616-sec8.html#sec8.2.4.

I experienced a similar situation whereby we had the same form posted a couple of times within milliseconds apart.

A packet capture via wireshark confirmed the retransmission by the browser and logs from the server indicated the arrival of the requests.

Also further investigation also revealed that the load balancer such as F5 have reported incidence of retransmission behavior. So it is worth checking with your load balancer vendor as well.