On Tue, Sep 21, 2010 at 12:10:49AM +0200, Jeroen Geilman wrote:
> On 09/21/2010 12:07 AM, Curtis wrote:
>> In the case where transport_maps is used to designate the next hop
>> destination of a message like this:
>>
>> customer.domain smtp:[mail.customer.domain]
>>
>> ...and the customer uses round robin dns for mail.customer.domain so that
>> it points to multiple IPs like this:
>>
>> mail.customer.domain. 900 IN A 111.111.111.111
>> mail.customer.domain. 900 IN A 222.222.222.222
>> mail.customer.domain. 900 IN A 333.333.333.333
>>
>> ....will postfix rotate between the ips that it delivers to?
>
> Yes.
Yes, when traffic to the destination is light (message deliveries
are spaced multiple seconds or more apart) or is very heavy (message
deliveries are many in each interval equal to the delivery of a single
message). When traffic is moderate, demand connection caching may
introduce some short-term bias towards recently used IPs. As the load
rises multiple connections are cached in parallel, and these will tend
to use all the available IPs.
--
Viktor.
