Load Balancing with Postfix [and SpamAssassin]

Ross Werner ross at agilestudios.com
Fri Jan 20 11:34:35 MST 2006

On Fri, 20 Jan 2006, Michael L Torrie wrote:
> On Fri, 2006-01-20 at 06:49 -0700, Josh Coates wrote
>> i'm not an email-original-designer-intention-historian, so please correct me
>> if i'm mistaken.
> I can't say if or where you are mistaken about the history of and the
> RFCs surrounding e-mail, but it appears e-mail was designed to be "best
> effort."  That is all.  There is no QoS for e-mail.

There's a huge difference between "no QoS" and "doesn't matter if you 
intentionally add delays", however. There's no QoS for AIM, for instance, 
but if AOL started started implementing a five-second delay for every 
message (maybe "to fight instant messaging spam"), you can bet users would 
be pissed.

Some people like and depend on the fact that 99% of their email is 
received and delivered within a few seconds, and a delay of an hour for a 
significant portion of those emails would throw off their groove. 
Greylisting would be a bad choice for these people.

Other people don't depend on that fact, and the delay doesn't bother them 
in the slightest. Greylisting would likely be a good choice for these 

The whole "best effort" excuse is pretty pitiful, in my opinion. IP does 
not provide any sort of QoS and is "best effort delivery", but if your ISP 
starts degrading IP performance, you're going to be upset.

 	~ Ross

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