I have an ssh tunnel that I am using to access an AWS ElasticSearch instance running in AWS, so that I can see Kibana in my browser. The tunnel is necessary because access is only allowed through a specific jump/gateway host that we have setup (this is very standard). I used to be able to access this just fine with http://localhost:9200/_plugin/kibana But then ElasticSearch updated something to require that the 'HOST' header contain the original host, ie: search-blahblahblahblah.us-east-1.es.amazonaws.com Ok, no matter, I'll just add an entry to my hosts file: 127.0.0.1 search-blahblahblahblah.us-east-1.es.amazonaws.com Now, I can curl just fine, and using Chrome works just fine too: http://search-blahblahblahblah.us-east-1.es.amazonaws.com:9200/_plugin/kibana But every time I try to use Firefox, it replaces the http with https, which obviously doesn't work because the tunnel is to port 80. Yes, I realize that *.amazonaws.com is owned by Amazon and they have an SSL cert. I have read a similar ticket, here: https://support.mozilla.org/en-US/questions/1209387 The acceptable answer in that ticket seemed to be to use a different domain for local development, which shouldn't be too hard to do, but in my case this is not a usable answer. I should be able to override Firefox and tell it not to change a URL that I have put into it, at least for specific sites.