HAProxy - Load balancer
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William Lallemand 631fd5f99b MEDIUM: acme: add dns-01 DNS propagation pre-check
When using the dns-01 challenge type, TXT record propagation across
DNS servers can take time. If the ACME server verifies the challenge
before the record is visible, the challenge fails and it's not possible
to trigger it again.

This patch introduces an optional DNS pre-check mechanism controlled
by two new configuration directives in the "acme" section:

  - "dns-check on|off": enable DNS propagation verification before
    notifying the ACME server (default: off)
  - "dns-delay <time>": delay before querying DNS (default: 300s)

When enabled, three new states are inserted in the state machine
between AUTH and CHALLENGE:

  - ACME_RSLV_WAIT: waits dns-delay seconds before starting
  - ACME_RSLV_TRIGGER: starts an async TXT resolution for each
    pending authorization using HAProxy's resolver infrastructure
  - ACME_RSLV_READY: compares the resolved TXT record against the
    expected token; retries from ACME_RSLV_WAIT if any record is
    missing or does not match

The "acme_rslv" structure is implemented in acme_resolvers.c, it holds
the resolution for each domain. The "auth" structure which contains each
challenge to resolve contains an "acme_rslv" structure. Once
ACME_RSLV_TRIGGER leaves, the DNS tasks run on the same thread, and the
last DNS task which finishes will wake up acme_process().

Note that the resolution goes through the configured resolvers, not
through the authoritative name servers of the domain. The result may
therefore still be affected by DNS caching at the resolver level.
2026-03-30 18:24:28 +02:00
.github CI: github: fix tag listing by implementing proper API pagination 2026-03-30 09:16:35 +02:00
addons MINOR: promex: export "haproxy_sticktable_local_updates" metric 2026-03-18 11:18:37 +01:00
admin CLEANUP: fix typos and spelling in comments and documentation 2026-03-30 09:24:19 +02:00
dev CLEANUP: fix typos and spelling in comments and documentation 2026-03-30 09:24:19 +02:00
doc CLEANUP: fix typos and spelling in comments and documentation 2026-03-30 09:24:19 +02:00
examples MINOR: mailers: warn if mailers are configured but not actually used 2025-06-27 16:41:18 +02:00
include MEDIUM: acme: add dns-01 DNS propagation pre-check 2026-03-30 18:24:28 +02:00
reg-tests MINOR: jwt: Manage ec certificates in jwt_decrypt_cert 2026-03-10 14:58:47 +01:00
scripts SCRIPTS: git-show-backports: add a restart-from-last option 2026-03-09 15:36:05 +01:00
src MEDIUM: acme: add dns-01 DNS propagation pre-check 2026-03-30 18:24:28 +02:00
tests TESTS: quic: add unit-tests for QUIC TX part 2025-09-08 14:49:03 +02:00
.cirrus.yml CI: cirrus-ci: bump FreeBSD image to 14-3 2025-10-09 14:06:48 +02:00
.gitattributes MINOR: Configure the cpp userdiff driver for *.[ch] in .gitattributes 2021-02-22 18:17:57 +01:00
.gitignore MINOR: tevt/dev: Add term_events tool 2025-01-31 10:41:50 +01:00
.mailmap DOC: update Tim's address in .mailmap 2021-09-16 09:14:14 +02:00
.travis.yml MEDIUM: mworker: remove USE_SYSTEMD requirement for -Ws 2024-11-20 12:07:38 +01:00
BRANCHES DOC: clarify the experimental status for certain features 2025-10-17 18:41:13 +02:00
BSDmakefile BUILD: makefile: commit the tiny FreeBSD makefile stub 2023-05-24 17:17:36 +02:00
CHANGELOG [RELEASE] Released version 3.4-dev7 2026-03-20 10:14:59 +01:00
CONTRIBUTING CLEANUP: assorted typo fixes in the code and comments 2025-04-02 11:12:20 +02:00
INSTALL MINOR: version: mention that it's development again 2025-11-26 16:11:47 +01:00
LICENSE LICENSE: add licence exception for OpenSSL 2012-09-07 13:52:26 +02:00
MAINTAINERS MAJOR: spoe: Let the SPOE back into the game 2024-05-22 09:04:38 +02:00
Makefile MEDIUM: acme: add dns-01 DNS propagation pre-check 2026-03-30 18:24:28 +02:00
README.md DOC: remove openssl no-deprecated CI image 2026-02-19 10:39:23 +01:00
SUBVERS BUILD: use format tags in VERDATE and SUBVERS files 2013-12-10 11:22:49 +01:00
VERDATE [RELEASE] Released version 3.4-dev7 2026-03-20 10:14:59 +01:00
VERSION [RELEASE] Released version 3.4-dev7 2026-03-20 10:14:59 +01:00

HAProxy

alpine/musl AWS-LC Illumos NetBSD FreeBSD VTest

HAProxy logo

HAProxy is a free, very fast and reliable reverse-proxy offering high availability, load balancing, and proxying for TCP and HTTP-based applications.

Installation

The INSTALL file describes how to build HAProxy. A list of packages is also available on the wiki.

Getting help

The discourse and the mailing-list are available for questions or configuration assistance. You can also use the slack or IRC channel. Please don't use the issue tracker for these.

The issue tracker is only for bug reports or feature requests.

Documentation

The HAProxy documentation has been split into a number of different files for ease of use. It is available in text format as well as HTML. The wiki is also meant to replace the old architecture guide.

Please refer to the following files depending on what you're looking for:

  • INSTALL for instructions on how to build and install HAProxy
  • BRANCHES to understand the project's life cycle and what version to use
  • LICENSE for the project's license
  • CONTRIBUTING for the process to follow to submit contributions

The more detailed documentation is located into the doc/ directory:

License

HAProxy is licensed under GPL 2 or any later version, the headers under LGPL 2.1. See the LICENSE file for a more detailed explanation.