Here's a strange one:
I've got nginx reverse proxying requests to apache 2 with mod_php.
A user (using firefox 3.1b3) reported that recently, he's started getting sporadic "What should firefox do with this file?" popups during normal navigation. We haven't had any other reports of this issue, and haven't been able to reproduce it ourselves.
I checked Nginx and apache's logs. Nothing in the error logs, and they both show a normal HTTP 200 for the request.
I had him send me the downloaded file, and it's generated HTML, as it should be -- except it has some trailing and leading bytes tacked on.
The opening byte sequence is the magic gzip header: 1F8B08
Here are the opening characters, C-escaped for convenience:
\x1F\x8B\x089608\r\n<!DOCTYPE HTML ...
and the file ends with:
...</html>\n\r\n0\r\n\r\n
When I fetch the same URL via wget, it starts with as expected; the mysterious opening and closing bytes are nowhere to be seen.
Has anyone ever seen anything similar to this? Could this be a FF 3.1b3 bug?