---

labels:

- 'Stage-Beta'

summary: 'Connection-level rate limiting'

...

Introduction

============

On some servers, especially public ones, it is desired to make sure that

everyone gets their fair share of system resources (and no more).

mod\_limits allows you to specify traffic bandwidth limits, preventing

any single connection hogging the server's CPU, RAM and bandwidth.

Details

=======

mod\_limits detects when a connection has exceeded its traffic allowance

and temporarily ignores a connection. Due to the way TCP and the OS's

network API works no data is lost, only slowed.

Configuration

=============

Currently mod\_limits is configured per connection type. The possible

connection types are:

-   c2s

-   s2sin

-   s2sout

-   component

The limits are specified like so in the **global** section of your

config (they cannot be per-host):

``` {.lua}

limits = {

  c2s = {

    rate = "3kb/s";

    burst = "2s";

  };

  s2sin = {

    rate = "10kb/s";

    burst = "5s";

  };

}

```

All units are in terms of *bytes*, not *bits*, so that "kb/s" is

interpreted as "kilobytes per second", where a kilobyte is 1000 bytes.

Compatibility

=============

  ----- -------------------

  0.9   Works

  0.8   Doesn't work(\*)

  ----- -------------------

(\*) This module can be made to work in 0.8 if you do two things:

1.  Install

    [util.throttle](http://hg.prosody.im/0.9/raw-file/d46948d3018a/util/throttle.lua)

    into your Prosody source's util/ directory.

2.  If you use libevent apply [this

    patch](http://prosody.im/patches/prosody08-mod-limits-fix.patch) to

    net/server\_event.lua.