=encoding utf-8

=head1 NAME

ngx_stream_limit_conn_module - Module ngx_stream_limit_conn_module




=head1



The C<ngx_stream_limit_conn_module> module (1.9.3) is used to
limit the number of connections per the defined key, in
particular, the number of connections from a single IP address.




=head1 Example Configuration




    
    stream {
        limit_conn_zone $binary_remote_addr zone=addr:10m;
    
        ...
    
        server {
    
            ...
    
            limit_conn           addr 1;
            limit_conn_log_level error;
        }
    }






=head1 Directives

=head2 limit_conn


B<syntax:> limit_conn I<I<C<zone>> I<C<number>>>



B<context:> I<stream>


B<context:> I<server>





Sets the shared memory zone
and the maximum allowed number of connections for a given key value.
When this limit is exceeded, the server will close the connection.
For example, the directives

    
    limit_conn_zone $binary_remote_addr zone=addr:10m;
    
    server {
        ...
        limit_conn addr 1;
    }


allow only one connection per an IP address at a time.





When several C<limit_conn> directives are specified,
any configured limit will apply.





The directives are inherited from the previous level if and
only if there are no
C<limit_conn>
directives on the current level.







=head2 limit_conn_log_level


B<syntax:> limit_conn_log_level I<
C<info> E<verbar>
C<notice> E<verbar>
C<warn> E<verbar>
C<error>>


B<default:> I<error>


B<context:> I<stream>


B<context:> I<server>





Sets the desired logging level for cases when the server
limits the number of connections.







=head2 limit_conn_zone


B<syntax:> limit_conn_zone I<
    I<C<key>>
    C<zone>=I<C<name>>:I<C<size>>>



B<context:> I<stream>





Sets parameters for a shared memory zone
that will keep states for various keys.
In particular, the state includes the current number of connections.
The I<C<key>> can contain text, variables,
and their combinations (1.11.2).
Connections with an empty key value are not accounted.
Usage example:

    
    limit_conn_zone $binary_remote_addr zone=addr:10m;


Here, the key is a client IP address set by the
C<$binary_remote_addr> variable.
The size of C<$binary_remote_addr>
is 4 bytes for IPv4 addresses or 16 bytes for IPv6 addresses.
The stored state always occupies 32 or 64 bytes
on 32-bit platforms and 64 bytes on 64-bit platforms.
One megabyte zone can keep about 32 thousand 32-byte states
or about 16 thousand 64-byte states.
If the zone storage is exhausted, the server will close the connection.








