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We develop a web application for internal use at our client sites, and it relies heavily on ajax requests. We have 20+ clients nationwide, many of whom are on the same version, and most with a high volume of users.

At only one client, we are seeing our ajax calls fail relatively frequently with status 12031 (ERROR_INTERNET_CONNECTION_RESET right?). "Frequently" meaning 0-10 times per day, whereas other clients of similar use/volume rarely ever, if at all, see this error (we log everything).

We can't seem to reproduce this, and are pretty sure it's due to their internal network flaking out. Are there any good tools or code we could use to analyze why this might be happening, and possibly figure out a recommendation? I doubt we'll be able to change, or even view, any router settings as we are just one small application on the massive internal network.

Thank you in advance!

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It seems that this is IE6/Ajax/SSL related. This link about sums up all the other research I've done: – Doug Johnson Sep 2 '11 at 22:50

If there's no load issues with the web server, it doesn't make a lot of sense for it to be throwing RST packets.

Something else spoofing the resets is certainly possible, and would point to a security device of some sort (firewall, IDS/IPS, or even a web filtering device) squashing the connection - anything like that in the network path?

It may be hard with that level of inconsistency with the errors, but if possible, capture the connection traffic with something like wireshark or tcpdump; whether the web server is truly sending the RST packets that the client is receiving is of particular interest.

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Thanks for the thoughts! I'll pass them along and see if anything comes of it. – Doug Johnson Sep 2 '11 at 21:59

If that is indeed the error, I would ask to share it with the infrastructure staff - VERY GENTLY! Say something like "we are looking over our application code and are having problems reproducing the problem. Since the error speaks to a possible underlying network interruption, we thought you might want to take a look as this might be causing issues elsewhere."

One possibility is the server NIC or switch port could be misconfigured or bad.

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Yeah we definitely have to tread lightly. :) Thanks for the thoughts. I'll pass them along and see if they spark any ideas. – Doug Johnson Sep 2 '11 at 21:59

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