I have a very annoying bug since a lot of time and I can't understand it.
I have a ajax call to a php script and sometimes (a little percentage) the parameters doesn't arrive I don't know why.
In the script I check for the parameters if it doesn't exist then I send to myself an email with some information to try to find the problem.
I send me: $_SERVER["HTTP_USER_AGENT"] and all the POST variables (doesn't arrive any of the POST variable, the list is empty).
Normally (not allways) the User Agent is:
"Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)" But I don't accept IE6 in the web and I have a little alert to warn this and the analytics doesn't show any IE6 visit)
Is it possible that anything arrives to the server and this USER AGENT is a default Agent and not the real one?
Then, please tell me possible causes of don't arrive anything and ideas of information to add to the mail to try to understand what happens.