Issue #21104 has been updated by alfl (Alex Flanagan). I can repro this on M4 chipset but not M3. `Fix is export RUBY_TCP_NO_FAST_FALLBACK=1` See https://github.com/rubygems/rubygems/issues/8390. ---------------------------------------- Bug #21104: Net::HTTP connections failing in Ruby >= 3.4.0 on macOS with Happy Eyeballs enabled https://bugs.ruby-lang.org/issues/21104#change-112788 * Author: mjt58 (Mike Thompson) * Status: Open * ruby -v: ruby 3.4.1 (2024-12-25 revision 48d4efcb85) +PRISM [arm64-darwin24] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- A project I work on recently upgraded Ruby to 3.4.1 from 3.3.5. Following the upgrade, and when running locally on my Mac, all attempts to connect to an external service within the project over http(s) fail. We use `mise` for managing development tool dependencies, including Ruby, and I am using macOS 15.3. For example running something as simple as: ``` require 'net/http' puts Net::HTTP.get(URI('https://bbc.co.uk')) ``` Will fail with the following stack trace: ``` /path/to/.local/share/mise/installs/ruby/3.4.1/lib/ruby/3.4.0/net/protocol.rb:46:in 'OpenSSL::SSL::SSLSocket#connect_nonblock': Connection reset by peer - SSL_connect (Errno::ECONNRESET) from /path/to/.local/share/mise/installs/ruby/3.4.1/lib/ruby/3.4.0/net/protocol.rb:46:in 'Net::Protocol#ssl_socket_connect' from /path/to/.local/share/mise/installs/ruby/3.4.1/lib/ruby/3.4.0/net/http.rb:1736:in 'Net::HTTP#connect' from /path/to/.local/share/mise/installs/ruby/3.4.1/lib/ruby/3.4.0/net/http.rb:1636:in 'Net::HTTP#do_start' from /path/to/.local/share/mise/installs/ruby/3.4.1/lib/ruby/3.4.0/net/http.rb:1625:in 'Net::HTTP#start' from /path/to/.local/share/mise/installs/ruby/3.4.1/lib/ruby/3.4.0/net/http.rb:1064:in 'Net::HTTP.start' from /path/to/.local/share/mise/installs/ruby/3.4.1/lib/ruby/3.4.0/net/http.rb:824:in 'Net::HTTP.get_response' from /path/to/.local/share/mise/installs/ruby/3.4.1/lib/ruby/3.4.0/net/http.rb:805:in 'Net::HTTP.get' from request.rb:2:in '<main>' ``` I tried different versions of Ruby and confirmed that the issue appears with 3.4.0. After reading the release notes for this version, I tried setting `RUBY_TCP_NO_FAST_FALLBACK=1` and this worked, allowing me to work around the problem. This issue has also been encountered by others, please see: https://github.com/rubygems/rubygems/issues/8390 -- https://bugs.ruby-lang.org/