I innocently did an
apt-get dist-upgrade today and suddenly
Apache wouldn't serve any static files, but anything generated by
CGI scripts worked super! Apache would send the headers for static
files complete with a Content-Length correctly but wouldn't send
any data in the HTTP response (even for an HTTP 200).
I spent hours trying to figure out what was going on under the assumption that I did a bad upgrade. I skimmed documentation, made sure my conf files were ok, did dozens of Google searches and then finally gave up and walked away for a couple of hours.
Long story short I finally hit gold with the right mantra of search terms and bumped into the EnableSendFile directive. I added:
to my Apache conf file and it works fine now.
I mention it in case someone else does a dist-upgrade with Debian testing on or around November 15th, 2006 and discovers themselves in the same boat.