Postfix rate limitai didžiausiems tiekėjams

/etc/postfix/transport

/\@gmail\.com$/       smtp-gmail:
/yahoo(\.[a-z]{2,3}){1,2}$/  yahoo:
/\@hotmail\.com$/ hotmail:
/\@live\.com$/ hotmail:
/\@msn\.com$/ hostmail:
/\@windowslive\.com$/ hotmail:

/etc/postfix/main.cf

transport_maps = regexp:/etc/postfix/transport
smtp_destination_concurrency_limit = 4
smtp_extra_recipient_limit = 2
smtp-gmail_destination_rate_delay = 12s
smtp-gmail_destination_concurrency_limit = 1
smtp-gmail_destination_recipient_limit = 2
smtp-gmail_initial_destination_concurrency=1
yahoo_initial_destination_concurrency = 1
yahoo_destination_concurrency_limit = 4
yahoo_destination_recipient_limit = 2
yahoo_destination_rate_delay = 1s
hotmail_destination_concurrency_limit = 2
hotmail_destination_rate_delay = 2s
hotmail_destination_recipient_limit = 5

/etc/postfix/master.cf

smtp-gmail unix -    -    n    -    1    smtp
      -o syslog_name=smtp-gmail
yahoo     unix  -       -       n       -       -       smtp
       -o syslog_name=postfix-yahoo
hotmail     unix  -       -       n       -       -       smtp
       -o syslog_name=postfix-hotmail

# postmap /etc/postfix/transport
# /etc/init.d/postfix restart