None of the Above (was Re: Sendmail still default?)

[Les Mikesell]

Nicolas Mailhot wrote:
> 
>>> Also filtering mail on MUA startup is just trainwreak recipe.
>>> If you want your MUA to start fast you need to pre-filter junk mail
>>> in
>>> the background (no not everyone uses gmail and gmail is not perfect
>>> anyway).
>>>
>>> So far, I haven't seen anything beating fetchmail + local MTA +
>>> server-side filters + local imap or local maildir delivery in
>>> Fedora.
>> But if you're using fetchmail, it's too late to filter -- because you
>> should be rejecting the stuff you don't want at SMTP time.
>>
>> Filtering wants to be done on the _real_ mail server that accepts
>> incoming mail.
> 
> Sure but many people do not have an ISP that provides clueful
> filtering, and even gmail is not so yummy when you take the privacy
> and no warranty bits into account.
> 
>> Doing it after fetchmail is almost as bad as doing it
>> in the MUA.
> 
> It's not. It means that when you start your MUA, everything is already
> available and filtered, instead for waiting for (10s or more) seconds
> with a massive CPU pike. That makes a huge user experience difference.

The problems are that you don't have a reasonable choice about what to 
do with questionable items at that point and the mail has already been 
accepted from the sender, establishing that you are a valid target if it 
really is spam, probably getting it put on widely sold lists. If your 
filter generates a bounce it will probably go to a forged address and 
contribute to the problem.  On the other hand if you don't generate a 
bounce and your filter is mistaken, you lose legitimate messages - or 
you have to save them in a folder that you manually check.  If you can 
scan during the smtp conversation with the sender you can just reject at 
that point making it someone else's problem.

-- 
   Les Mikesell
     lesmikesell at gmail.com