[thirdparty/pdns.git] / pdns / dnsdistdist / docs / advanced / qpslimits.rst

Rules for traffic exceeding QPS limits
======================================

Traffic that exceeds a QPS limit, in total or per IP (subnet) can be matched by the :func:`MaxQPSIPRule`-rule. For example:

.. code-block:: lua

  addAction(MaxQPSIPRule(5, 32, 48), DelayAction(100))

This measures traffic per IPv4 address and per /48 of IPv6, and if UDP traffic for such an address (range) exceeds 5 :term:`qps`, it gets delayed by 100ms.

As another example:

.. code-block:: lua

  addAction(MaxQPSIPRule(5), NoRecurseAction())

This strips the Recursion Desired (RD) bit from any traffic per IPv4 or IPv6 /64 that exceeds 5 qps. This means any those traffic bins is allowed to make a recursor do 'work' for only 5 qps.

If this is not enough, try:

.. code-block:: lua

  addAction(MaxQPSIPRule(5), DropAction())
  -- or
  addAction(MaxQPSIPRule(5), TCAction())

This will respectively drop traffic exceeding that 5 QPS limit per IP or range, or return it with TC=1, forcing clients to fall back to TCP.

To turn this per IP or range limit into a global limit, use ``NotRule(MaxQPSRule(5000))`` instead of :func:`MaxQPSIPRule`.
Commit	Line	Data
20d81666 PL	1	Rules for traffic exceeding QPS limits
	2	======================================
	3
	4	Traffic that exceeds a QPS limit, in total or per IP (subnet) can be matched by the :func:`MaxQPSIPRule`-rule. For example:
	5
	6	.. code-block:: lua
	7
832c1792	8	addAction(MaxQPSIPRule(5, 32, 48), DelayAction(100))
20d81666	9
e87c3dd0	10	This measures traffic per IPv4 address and per /48 of IPv6, and if UDP traffic for such an address (range) exceeds 5 :term:`qps`, it gets delayed by 100ms.
20d81666 PL	11
	12	As another example:
	13
	14	.. code-block:: lua
	15
	16	addAction(MaxQPSIPRule(5), NoRecurseAction())
	17
	18	This strips the Recursion Desired (RD) bit from any traffic per IPv4 or IPv6 /64 that exceeds 5 qps. This means any those traffic bins is allowed to make a recursor do 'work' for only 5 qps.
	19
	20	If this is not enough, try:
	21
	22	.. code-block:: lua
	23
	24	addAction(MaxQPSIPRule(5), DropAction())
	25	-- or
	26	addAction(MaxQPSIPRule(5), TCAction())
	27
	28	This will respectively drop traffic exceeding that 5 QPS limit per IP or range, or return it with TC=1, forcing clients to fall back to TCP.
	29
	30	To turn this per IP or range limit into a global limit, use ``NotRule(MaxQPSRule(5000))`` instead of :func:`MaxQPSIPRule`.