title: how to configure Postfix to send more emails per hour than the default
body: <p>My postfix only let me send only 3600 email in an hour ( from which i conclude that there is 1s delay between each email ) while I want to send double that number .. I looked in the postfix configuration .Is there any parameters that i can change to send more than 3600 email in an hour ?
  this is the output of <code>postconf -n</code></p>
  
  <pre><code>alias_database = hash:/etc/aliases
  alias_maps = hash:/etc/aliases
  bounce_queue_lifetime = 1d
  command_directory = /usr/sbin
  config_directory = /etc/postfix
  daemon_directory = /usr/libexec/postfix
  data_directory = /var/lib/postfix
  debug_peer_level = 2
  default_destination_concurrency_limit = 5
  default_destination_rate_delay = 0s
  html_directory = no
  inet_interfaces = all
  inet_protocols = ipv4
  initial_destination_concurrency = 2
  lmtp_destination_rate_delay = 0s
  local_destination_rate_delay = 0s
  mail_owner = postfix
  mailq_path = /usr/bin/mailq.postfix
  manpage_directory = /usr/share/man
  maximal_queue_lifetime = 1d
  mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain
  mydomain = example.com
  myhostname = server01.example.com
  myorigin = $mydomain
  newaliases_path = /usr/bin/newaliases.postfix
  qmgr_message_recipient_limit = 10000
  queue_directory = /var/spool/postfix
  readme_directory = /usr/share/doc/postfix-2.5.6/README_FILES
  relay_destination_rate_delay = 0s
  sample_directory = /usr/share/doc/postfix-2.5.6/samples
  sendmail_path = /usr/sbin/sendmail.postfix
  setgid_group = postdrop
  smtp_bind_address = xxx.xxx.xxx.xxx
  smtp_destination_rate_delay = 0s
  smtp_generic_maps = hash:/etc/postfix/generic
  smtpd_banner = $myhostname ESMTP $mail_name
  smtpd_client_restrictions = check_client_access hash:/etc/postfix/access
  unknown_local_recipient_reject_code = 550
  virtual_alias_maps = hash:/etc/postfix/virtual
  virtual_destination_rate_delay = 0s
  </code></pre>