connection_limit

Specifies the maximum number of concurrent connections that will be made from the current MTA machine to the destination site.

kumo.on('get_egress_path_config', function(domain, source_name, site_name)
  return kumo.make_egress_path {
    connection_limit = 32,
  }
end)

Since: Version 2025.01.23-7273d2bc

The functionality described in this section requires version 2025.01.23-7273d2bc of KumoMTA, or a more recent version.

connection_limit may now be specified using a string in addition to an integer; the string format allows the use of commas or underscores to separate digits if you prefer that for clarity:

kumo.on('get_egress_path_config', function(domain, source_name, site_name)
  return kumo.make_egress_path {
    connection_limit = '1,000',
  }
end)

kumo.on('get_egress_path_config', function(domain, source_name, site_name)
  return kumo.make_egress_path {
    connection_limit = '1_000',
  }
end)

However, the primary reason for supporting the string notation is that you can indicate when you wish for the connection limit to be local to the kumod instance, rather than shared via redis.

In the example below, we force the use of a local connection limit even if redis-shared throttle and limits are enabled:

kumo.on('get_egress_path_config', function(domain, source_name, site_name)
  return kumo.make_egress_path {
    connection_limit = 'local:20',
  }
end)