[AktiviX-discuss] dying under the spam

[ana]

> max* wrote:

> >> Greylisting is a technique where when a mailserver temporarily rejects
> >> email from new senders.  The senders mailserver will queue the mail and
> >> retry later. 

The problem with this is that it doesn't always happen. 

mp wrote:

> But if it is based on the concept that all mail
> follows anyway, i.e., resending until accepted, then I cannot see how
> there should be any problems.

The problem is that not all mail follows.
 
> "servers that don't handle it well", 

Greylisting works when the rest of the servers that send you email do it 
as well. In the same way that sending a .doc file to someone only works if 
the receiving person also has Word, or a program that "handle .doc files 
well".

In fact, its effectiveness with spam relies on the fact that servers 
sending spam do not usually try a second time. But there are also servers 
sending legitimate mail that do not try a second time either, or they try 
immediately, or too late for the greylisting to work. The result is that 
legitimate emails sent from those servers that do not try again properly 
(or, "don't handle greylisting well"), do not get to the recipient. They 
do generate a temporary error (450 I seem to remember?), which is received 
at the sending server, but sending  servers, in my experience, do not tend 
to deliver these messages to the  sending address, and the initial email  
does _not_ get delivered (that's the whole point of greylisting - not 
delivering emails that are suspected to be spam on the basis that the 
sending server does not try again after receiving the temporary error 
message).

Then the user/s tend to realise of the problem when they notice that they 
have not received quite a few emails from a certain domain. Then they 
contact the server administrator/s, who will need to explain that those 
emails they haven't receive are lost forever, and they will need to ask 
the sender to re-send those emails, but hang on, only after we have  
manually "whitelisted" (or expempted) either that address, or that domain, 
or IP address, so that the greylisting does not apply to them.

... And the reason why I would oppose to greylisting is because I don't 
think aktivix has the capacity to give support to all complaints and 
spend as much time manually doing the whitelisting for people like some 
proffesional ISP would do...

Other than that, I'm quite happy with the reduction we've already noticed 
in spam volume :)

ana