What is the curl error 52 “empty reply from server”?

Question

I have a cron job setup on one server to run a backup script in PHP that is hosted on another server.

The command I\'ve been using is

curl -sS http://w         


        

Answer 1

In case of SSL connections this may be caused by issue in older versions of nginx server that segfault during curl and Safari requests. This bug was fixed around version 1.10 of nginx but there is still a lot of older versions of nginx on the internet.

For nginx admins: adding ssl_session_cache shared:SSL:1m; to http block should solve the problem.

I'm aware that OP was asking for non-SSL case but since this is the top page in goole for "empty reply from server" issue, I'm leaving the SSL answer here as I was one of many that was banging my head against the wall with this issue.