Re: spam and well known smtp servers

[Cerberus - the Guardian of Hades]

i need to unsubscribe:

[EMAIL PROTECTED]
[EMAIL PROTECTED]
[EMAIL PROTECTED]

from this list as he is no longer a user at this server. please help.

regards,
mark

On Wed, 5 Jul 2000, Erwin Hoffmann wrote:

> Hi again,
> 
> At 22:37 4.7.2000 +0200, Andre Oppermann wrote:
> >Erwin Hoffmann wrote:
> >> 
> >> Hi,
> >> 
> >> since I'm dealing with the SPAMCONTROL patch, I would like to comment your
> >> problem:
> >> 
> >> 1. You are right. Within the filtering mechanisms a logical "AND" scheme is
> >> missing. To implement this requires some attention.
> >> 
> >> 2. Principally the following checks could be applied:
> >> 
> >> Logic:
> >> a) The envelope's MAIL FROM: address has to be taken.
> >> b) From TCPENV the REMOTEIP has to be taken (=> real Sender IP)
> >> c) By means of a DNS A-Lookup(MAIL FROM: address) the (let's call it)
> >> pretended IP address has to be evaluated.
> >> 
> >> Assumption:
> >> For legitamate E-Mails both IP addresses belong (usually) to the same IP
> >> subnet. However, one has to define a range of significant IP address bits
> >> to evaluate (common in the CIDR scheme).
> >
> >Unfortunatly this assumption is pretty much flawed. For example I have
> >two IP ranges, 195.134.128/19 and 62.48.0.0/19. Now my customers are
> >usually in the 195 range but my mail servers are in the 62 range. So
> >how do you propose to handle that?
> 
> Yes, I know about that. The other attempt is to use static IP adresses as
> Markus' proposed. Both schemes could be combined. Let's assume we have an
> additional control file ./stmpallowedfrom:
> 
> hotmail.com:195.111.222.200/19                (address range)
> fehcom.de:195.162.195.1,195.162.195.2         (list of static ip addresses)
> 
> This would give you some possibilty without the need to really now what are
> the  IP adresses of an SMTP sender. The address parsing is a little tricky.
> 
> 
> eh.
> 
> >
> >> Result:
> >> => Comparing both IP addresses would effectively eliminate reception of
> >> E-mail thru 3rd party relays, as in your case.
> >> 
> >> I think about but don't promise anything. There are other items on my
> agenda.
> >
> >-- 
> >Andre
> >
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