[Answered ]-Django Haystack reporting `Errno 111: Connection Refused` connecting to Solr

The problem seems to have been caused by a recent system update that updated Jetty, the HTTP server I’m using to run Solr. It was refusing connections, because its settings file only allowed certain users. So I edited /etc/default/jetty to contain this line:

JETTY_HOST=0.0.0.0

So it now accepts all incoming connections, solving the problem. You can also specify the specific connection that Django will be using, to limit the possibility of abuse.