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Take the following internal round robin dns setup IN A IN A IN A IN A IN A IN A IN A IN A IN A IN A

Now assume the following postfix setup (assume these are the only tweaks from defaults in debian package)

smtp_connection_cache_destinations =
smtp_connection_cache_reuse_limit = 750
smtp_destination_concurrency_limit = 75


* :[]

I would expect 75 concurrent connections spread across the 10 A records I've set in DNS. However I'm seeing more than a few hundred connections to and I'm wondering if Postfix is "smart" enough to set up 75 concurrent connections for each IP address.


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Can I ask why you would want to setup this scenario? What is the end goal? – pablo Feb 12 '11 at 15:24

1 Answer 1

You should read this: (Tuning the number of simultaneous deliveries)

and also understanding how resolver work in Linux might help to avoid such "solutions" in the future ;)

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