title: nginx proxy: connect() to ip:80 failed (99: Cannot assign requested address)
body: <p>An nginx/1.0.12 running as a proxy on Debian 6.0.1 starts throwing the following error after running for a short time:</p>
  
  <pre>
  connect() to upstreamip:80 failed (99: Cannot assign requested address) 
  while connecting to upstream, client: xxx.xxx.xxx.xxx, server: localhost, 
  request: "GET / HTTP/1.1", upstream: "http://upstreamip:80/", 
  host: "requesteddomain.com"
  </pre>
  
  <p>Not all requests produce this error, so I suspect that it has to do with the load of the server and some kind of limit it hit.</p>
  
  <p>I have tried raising ulimit -n to 50k and worker_rlimit_nofile to 50k as well, but that does not seem to help. lsof -n shows a total of 1200 lines for nginx.
  Is there a system limit on outgoing connections that might prevent nginx from opening more connections to its upstream server?</p>