This Integer32 object caps the number of child processes each proxy daemon is allowed to run simultaneously, with a value of zero meaning unlimited; the desc notes this limit does not apply to the SMTP proxy. An administrator uses this to prevent a single busy proxy, such as the HTTP proxy under heavy load, from spawning enough child processes to exhaust system resources. For example, setting this to 50 would cap a proxy daemon at 50 concurrent child processes even during a traffic spike.