From 22a6a0bc6b5ab9358f620043e87352d9ae8d7294 Mon Sep 17 00:00:00 2001 From: Daniel Stenberg Date: Fri, 30 Aug 2024 09:04:15 +0200 Subject: [PATCH] http3.md: mention how the fallback can be h1 or h2 Closes #14736 --- docs/cmdline-opts/http3.md | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/docs/cmdline-opts/http3.md b/docs/cmdline-opts/http3.md index a1900655a0..fa3d7c3801 100644 --- a/docs/cmdline-opts/http3.md +++ b/docs/cmdline-opts/http3.md @@ -20,14 +20,16 @@ Example: # `--http3` Attempt HTTP/3 to the host in the URL, but fallback to earlier HTTP versions -if the HTTP/3 connection establishment fails. HTTP/3 is only available for -HTTPS and not for HTTP URLs. +if the HTTP/3 connection establishment fails or is slow. HTTP/3 is only +available for HTTPS and not for HTTP URLs. This option allows a user to avoid using the Alt-Svc method of upgrading to -HTTP/3 when you know that the target speaks HTTP/3 on the given host and port. +HTTP/3 when you know or suspect that the target speaks HTTP/3 on the given +host and port. When asked to use HTTP/3, curl issues a separate attempt to use older HTTP versions with a slight delay, so if the HTTP/3 transfer fails or is slow, curl -still tries to proceed with an older HTTP version. +still tries to proceed with an older HTTP version. The fallback performs the +regular negoatiaion between HTTP/1 and HTTP/2. Use --http3-only for similar functionality *without* a fallback. -- 2.47.3