> If you look at custom map lists inside the server.tab file and you use :
> 
> sbl.spamhaus.org:-10
> 
> you will get that if the SMTP client is listed inside such list, XMail
> will push a 10 seconds delay between each SMTP command.
> 
> - Davide



Your reply gives me a lot of hope from the technical point of view and I would 
certainly like to hear about the results of that method in "real life"!

However - and please do not consider that as a lack of appreciation - I would 
really expect limited results from that method - for a number of reasons (some 
of which were already listed as "obvious problems" in my first post):

1) the total delay is rather small (30-40 seconds) for a "known spammer" and 
maybe a little high for a server that was marked as bad by mistake (or more 
likely by "blacklisting" an entire IP class - which will no longer be such a 
major problem with the adaptative method - as long as he will only send you 
very few emails!);

2) probably the most important problem - the method ONLY works for "manually 
blacklisted" spammers (and for instance will be completely useless against 
small one-time "spam relays" that "jump" from one host to another); only for 
that reason and I would say that the effectiveness can not be higher than 10%!

3) manually blacklisting each spammer is something that an administrator would 
rather avoid :) (this also probably means that an automated way to use one of 
the large "blacklists" might be a strong incentive);

4) without a limit on the number of simultaneous connections from the same 
IP/class/domain the efficiency can not be very high! even more, a large 
persistent spammer can "block" your server for a very long time by trying to 
send you a very large number of emails on all your receiving threads (but after 
a second thought that is not very likely - I think that the default limit is 
1024 threads :)

5) without the adaptative part the efficiency can not be very high - why would 
you want to let a persistent known spammer send you 1000 emails with a constant 
delay of 30 seconds (which can be very little if he can open 100 parallel 
connections) when ideally you would like to force him to send only one email at 
a time, with a delay in the range of 70-80 seconds for the first email, then 
200-300 seconds for the next 2-10 emails and after that you would like to 
reject any other email from him for the next 12 hours!

Anyway, I feel that we are on the "right direction" and that something good can 
come out of this!

Best regards,
Catain Caranfil
-
To unsubscribe from this list: send the line "unsubscribe xmail" in
the body of a message to [EMAIL PROTECTED]
For general help: send the line "help" in the body of a message to
[EMAIL PROTECTED]

Reply via email to