DOC: quic: fix recommandation for bind on multiple address

Documentation falsely mentions that binding on multiple addresses is
forbidden for QUIC listeners. This is not the case. Moreover, this
behavior is reliable when using destination address retrieval on receive
via IP_PKTINFO, which allows to determine the proper source address for
response.

This should be backported up to 2.7. On 2.6 specific source address
definition on sendmsg via IP_PKTINFO is not implemented. As such, bind
on multiple addresses should remain forbidden for this release.

diff --git a/doc/configuration.txt b/doc/configuration.txt
index 1065e60989884824835a7a3db24d59434c8d516d..1b35e0141ffbd1707533de5d6196a4ace053096b 100644 (file)
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -5383,10 +5383,12 @@ bind /<path> [, ...] [param*]
                   listen on. If unset, all IPv4 addresses of the system will be
                   listened on. The same will apply for '*' or the system's
                   special address "0.0.0.0". The IPv6 equivalent is '::'. Note
-                  that if you bind a frontend to multiple UDP addresses you have
-                  no guarantee about the address which will be used to respond.
-                  This is why "0.0.0.0" addresses and lists of comma-separated
-                  IP addresses have been forbidden to bind QUIC addresses.
+                  that for UDP, specific OS features are required when binding
+                  on multiple addresses to ensure the correct network interface
+                  and source address will be used on response. In other way,
+                  for QUIC listeners only bind on multiple addresses if running
+                  with a modern enough systems.
+
                   Optionally, an address family prefix may be used before the
                   address to force the family regardless of the address format,
                   which can be useful to specify a path to a unix socket with