Question

If I make multiple HTTP Get Requests to the same server and get HTTP 200 OK responses to each one how do I tell which request maps to which response using Wireshark?

Currently it looks like an http request is made, and the next HTTP 200 OK response is quickly received so everything is in a the proper sequence. I have seen things to the contrary however. For example using the Google Maps API v2 I’ve made several requests for location information and then the information is received in an arbitrary order (closely resembling the order in which I requested it, but not necessarily perfect.)

So my intuition is I cannot assume that my responses will be received in a specific order, even though they may be in order most of the time. So I’m wondering how I can determine this order from the response.

Update: Clarification as to what I need. I just need to know that the server has received the request. It seems like I need to do this by looking at sequence numbers and perhaps even ACKS. The reasoning behind this approach is I’m basically observing a web app and checking it is sending the information and the information is being received.

Update: This has nothing to do with wireshark specifically. I believe it is confusing people so I removing it from the title. It has to do with the HTTP protocol on top of the TCP/IP protocol and how we map responses to requests.

Thanks.

Answer 1

Seems like this ability is not provided by the HTTP protocol at the application layer so I must go down to the transportation layer to determine this. In my case the TCP/IP layer using sequence numbers.

HTTP only presumes a reliable
transport; any protocol that provides
such guarantees can be used; the
mapping of the HTTP/1.1 request and
response structures onto the
transport data units of the protocol
in question is outside the scope of
this specification.

Read more:
http://www.faqs.org/rfcs/rfc2616.html#ixzz0e20kxKcz