Loosing spam fight

[Roland Smith]

On Sat, Jan 27, 2007 at 01:04:28PM -0200, JoaoBR wrote:
> > Greylisting is a decent idea, but it seems to me that it's just another
> > tool in the ongoing arms race against spammers. It may work for a while,
> > but eventually they'll catch on and it will only cause unnecessary delays
> > for legitimate mail.
> >
> 
> finally some cares about the users here, that is a really important
> point, how do you justify that your client get the email he is waiting
> for an hour later? Probably he looks then for a better service
> provider ...

The standard requires a retry time of at least 30 minutes:
http://tools.ietf.org/html/rfc2821#section-4.5.3 

But most open-source MTA's will try to resend after around 15 minutes:
http://en.wikipedia.org/wiki/Greylisting 

Note that the SMTP protocol does not guarantee delivery within a certain
timeframe. 

There are timeouts of several minutes for each of the SMTP
commands. This means that a full SMTP conversation can last at least 1/2
hour, from one server to another.

In short, an extra hour transit time is not a fault or bad service as
far as SMTP is concerned.

Roland
-- 
R.F.Smith                                   http://www.xs4all.nl/~rsmith/
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