HTTP/2 Reverse Proxy

[Russel_]

I have Nginx (1.9.12) setup and working fine with HTTP/2 on host-a. I can
establish HTTP/2 connections to host-a with any web browser. I also have
HTTP/2 and proxypass setup on host-b. I can proxy HTTP/1.1 requests from
host-b to host-a with any web browser. I can also establish HTTP/2
connections with host-b using any web browser. However, I can't get the
proxy request from host-b to host-a to talk HTTP/2. The connection between
host-b and host-a doesn't utilize the TLS ALPN extension so that the h2
protocol can be used. A packet capture shows that HTTP/1.1 is used for the
proxy connection between host-b and host-a despite the fact that virtual
host on host-a is configured to only accept h2 connections. Is there a way
to force the use of the TLS ALPN extension?

Thanks for your time,
Russel

Posted at Nginx Forum: https://forum.nginx.org/read.php?2,264954,264954#msg-264954