maillscanner/postfix saturates bandwidth :-(

C. Jon Larsen jlarsen at
Mon Sep 24 20:58:21 IST 2012

> You can play with variations of these settings in main.conf to control how
> much email is sent out - these go into main.conf

[Sorry, I meant to say]

Also you can use generic os based or (if you dont want to touch the 
hosts involved) router based traffic shaping on 
outbound smtp. If you have a cisco router you can write an acl to 
match outbound smtp traffic and rate shape it as it passes an interface 

interface Gigabit0/0
  ! uplink
  traffic-shape group 161 1250000
interface Gigabit0/1.101
  ! downlink
  traffic-shape group 161 1250000

access-list 161 remark smtp traffic shaping
access-list 161 permit tcp a.b.c.d 0.0.0.x any eq 25
access-list 161 permit tcp any eq 25 a.b.c.d 0.0.0.x

x = 0 if you are matching a single host, or you can use say if you 
need to match a /20 worth of mail servers.

If you are natting between the interfaces you will also need to take that 
into acct on the acl.

> local_destination_concurrency_limit = 2
> default_destination_concurrency_limit = 2
> initial_destination_concurrency = 2
> smtpd_client_connection_count_limit = 10
> default_destination_recipient_limit = 20

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