Here's what Return Path has to say about connections and throughput settings and limits, this is very general: Obviously these things are handled very differently by individual domains, but this is something to consider for sure. But when it comes to testing, you gotta start somewhere, right!?
I wanted to quickly post up an example of what I'm talking about as far as the way things are handled at the domain level, here's the way Bluetie (Excite) does it:
It's always good to know the minimums, too bad they don't post the maximums. In general, it's all about finding that sweet spot. Domains like comcast allow higher throttles based on your SenderScore, and domains like SBCGlobal limit your connections to only 1 or you'll just junk immediately. Of course they're going to recommend 150 max connections. But can you achieve the same results at 250? 500? Time is money.
