Supported HTTP versions for requests and responses

HTTP/1.1 and HTTP/1.0

HTTP/1.0 requests are sent to junctioned back-end servers only if those servers return a status of 400 (Bad Request), return a status of 504 (HTTP version not supported), or if the client browser specifies HTTP/1.0 in the request. Otherwise, if the back-end server accepts HTTP/1.1, WebSEAL sends HTTP/1.1 requests. However, even when WebSEAL sends an HTTP/1.0 request to a junctioned back-end server (and the back-end server returns an HTTP/1.0 response), WebSEAL always returns an HTTP/1.1 response to the client browser.

HTTP/2

HTTP/2 support can be enabled on a per junction basis. WebSEAL only uses HTTP/2 to junction servers or proxies used to access the junctions when the junctions are configured to use HTTP/2. It will not attempt to use or fall back to HTTP/1.1 or earlier versions. For SSL junctions, the connection uses ALPN with only "h2". The junction server must accept the "h2". For TCP junctions, the connection uses the "prior knowledge" method (RFC 7540 Section 3.4).

Parent topic: Technical notes for using WebSEAL junctions