``tls``
Specifies configuration information for a TLS connection, including a ``key-file``, ``cert-file``, ``ca-file`` and ``hostname``.
+ ``http``
+ Specifies configuration information for an HTTP connection, including ``endponts``, ``listener-clients`` and ``streams-per-connection``.
+
``trust-anchors``
Defines DNSSEC trust anchors: if used with the ``initial-key`` or ``initial-ds`` keyword, trust anchors are kept up-to-date using :rfc:`5011` trust anchor maintenance; if used with ``static-key`` or ``static-ds``, keys are permanent.
when encryption is handled by third-party software or by a reverse
proxy).
+``http-listener-clients``
+ This sets the hard quota on the number of active concurrent connections
+ on a per-listener basis. The default value is 300; setting it to 0
+ removes the quota.
+
+``http-streams-per-connection``
+ This sets the hard limit on the number of active concurrent HTTP/2
+ streams on a per-connection basis. The default value is 100;
+ setting it to 0 removes the limit. Once the limit is exceeded, the
+ server finishes the HTTP session.
+
``dscp``
This is the global Differentiated Services Code Point (DSCP) value to
classify outgoing DNS traffic, on operating systems that support DSCP.
``endpoints``
A list of HTTP query paths on which to listen. This is the portion
of an :rfc:`3986`-compliant URI following the hostname; it must be
- an absolute path, beginning with "/". A typical endpoint is "/dns-query".
+ an absolute path, beginning with "/". The default value
+ is ``"/dns-query"``, if omitted.
+
+ ``listener-clients``
+ The option specifies a per-listener quota for active connections.
+
+ ``streams-per-connection``
+ The option specifies the hard limit on the number of concurrent
+ HTTP/2 streams over an HTTP/2 connection.
+
+Any of the options above could be omitted. In such a case, a global value
+specified in the ``options`` statement is used
+(see ``http-listener-clients``, ``http-streams-per-connection``.
For example, the following configuration enables DNS-over-HTTPS queries on
all local addresses:
added to add a list of servers to a zone that can be used for checking DS
presence. :gl:`#1126`
+- It is now possible to set a hard quota on the number of concurrent DoH
+ connections, and the number of active HTTP/2 streams per connection,
+ by using the ``http-listener-clients`` and ``http-streams-per-connection``
+ options, or the ``listener-clients`` and ``streams-per-connection``
+ parameters to an ``http`` statement. The defaults are 300 and 100
+ respectively. :gl:`#2809`
+
Removed Features
~~~~~~~~~~~~~~~~