PHP Uploading with FastCGI on IIS 7.5 stalling/taking forever

Question

Okay first off; this works 100% okay on one server set up, but is messed up on a very similar one - which is why I think it has to be an IIS issue somewhere - I just don't know where.

I have a very standard PHP upload script, but it keeps locking up/freezing then resuming itself on larger files (over 250mb.)

No errors return, and the upload does finish and work fine for files up to 4gb - but it takes forever. You can watch the size of the tmp files as they upload, and it will just stop receiving data - sometimes for several minutes at a time, then just pick back up right where it left off and continue the upload.

I have configured the following in IIS:

CGI:

• Time-out: 00:30:00
• Activity Timeout: 300000
• Idle Timeout: 300000
• Request Timeout: 300000

Request Filtering:

• Max allowed content length: 4294967295
• Max URL Length: 4096
• Max query string: 2048

PHP:

• post_max_size: 4G
• upload_max_filesize: 4G
• max_execution_time: 300000
• max_file_uploads: 300000
• max_input_time: -1
• memory_limit: -1

I was previously getting errors from the script taking too long, however upping the Activity, Idle, and Request times have fixed that issue. The uploads do work fine, but take FOREVER. I have the exact same IIS settings on another dev box running the same upload script and it works flawlessly - so I don't know what I'm missing.

PHP is 5.4.14. I get nothing in the PHP error log or Windows Event Viewer (since no errors are actually thrown as far as I can tell.)

Anyone have any idea of what settings I could be missing somewhere?

Answer 1

Welp, that was stupid. I just asked around and someone did infact turn on "intrusion prevention" at the router level for the one server that was having issues. Disabling that seems to resolve the problem.