[UA-EAI] UASG014 - Quick Guide to EAI

[Arnt Gulbrandsen]

> 3) Should we identify UASG Good Practices where they are not 
> addressed one way or another within the RFCs?   Eg Aliasing vs 
> ‘downgrading’ on the fly.

JFYI, there's anything up to 2.5 million MTAs deployed with EAI support 
now. (It's difficult to tell exactly since a majority has the support 
disabled in a configuration file. But a couple of million is a good guess. 
Roughly a million for each of Postfix and Exim, and a few tens of thousands 
for up to ten other MTAs.)

Don't identify any "good practice" that's at odds with either Postfix or 
Exim. Even if something was a good idea, the deployed code is better by 
virtue of being deployed. What we need now is agreement and interoperation.

Anyone who argues that some significant deviation from Postfix/Exim is a 
good idea risks being heard as saying "the 2008-era RFCs were bad, the 
2012-era RFCs were bad, the 2014-16 implementations were bad but THIS time 
we've got it right". I realise that's not the intention, but it might well 
be the perception, and that perception would be harmful to further 
deployment.

Arnt