On 8/14/2013 10:12 AM, Philippe Bloix wrote: > Of course it's easy to contact our customers! > But in some cases, it can be difficult to contact the mail provider of our > customers in order to ask to belong to their whitelist...
If this is truly the case and this is legitimate transactional mail, then contacting the receiving organizations is the proper way to go about this. But since this is difficult, there are some other things you can try before implementing a multi-instance or multi-host relay farm. For instance, setting smtp_destination_concurrency_limit to a low value. The default value is that of default_destination_concurrency_limit (default: 20) Decreasing parallel connections will decrease your msg rate. Start with a value of 2 and see if that works, and if delivery rate is acceptable to you. If yes, and no, increase by 2 until you hit rate limiting at the receivers or you find the msg rate acceptable. If you run into rate limiting, decrease by two, and keep the resulting value. Receivers may also be rejecting you for delivering too many recipients/msg, not purely inbound msg or connection rate, if they count total recipients delivered instead of msgs accepted by smtpd. So you can try lowering the value of smtp_destination_recipient_limit to 25, lower if necessary. The default value is that of default_destination_recipient_limit (default: 50) Do NOT set this value lower than 2. See the postconf (5) entry for why. By tweaking the two values above it should be possible to avoid your rate limiting problem but without dropping delivery rate all the way down to 1/sec. The above are global settings. You can also do this on a per receiving domain basis by using a transport table and a corresponding custom master.cf message delivery transport. See: http://www.postfix.org/postconf.5.html#transport_destination_concurrency_limit http://www.postfix.org/postconf.5.html#transport_destination_recipient_limit -- Stan
