Nginx reverse proxy to Heroku fails SSL handshake

ssl heroku nginx configuration reverse-proxy

I was able to solve this today and wanted to post the solution in case others run into the same issue.

It turns out that the problem was related to SNI after all. I found this ticket on nginx.org:

Which led me to the proxy_ssl_server_name directive:

By setting to "on" in your config, you'll be able to proxy to upstream hosts using SNI.

Thanks to all who commented with suggestions!

ssl heroku nginx configuration reverse-proxy

As a note for others a related condition that Heroku imposes is that the HOST field must match the custom domain name.

So in addition to proxy_ssl_server_name you may also want to set a line like:

proxy_set_header Host mycustomdomain.com;

Of course this only applies if the host field incoming into the sever is different from the domain that your server resides in.

The specific error you get is:

SSL certificate error
There is conflicting information between the SSL connection, its certificate and/or the included HTTP requests.

ssl heroku nginx configuration reverse-proxy

Please try by adding proxy_ssl_server_name on

location ^~ /proxiedpath/ {    proxy_ssl_server_name on; }

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