Can Spamassassin identify spam from DSL or Cable?

["Hou, Ming" <Mi...@NJIT.EDU>]

Hi,

I am using Spamassassin 2.63. I am wondering can Spamassassin determine
that the last hop of the mail relay is a legitimate DSL /Cable modem
mail server?   

Thanks,
ming

Re: Can Spamassassin identify spam from DSL or Cable?

[Matt Kettler <mk...@evi-inc.com>]

At 01:34 PM 8/4/2004, Hou, Ming wrote:
>I am using Spamassassin 2.63. I am wondering can Spamassassin determine 
>that the last hop of the mail relay is a legitimate DSL /Cable modem mail 
>server?

No. AFAIK there's no such thing as known listing of "legitimate" 
mailservers for dsl/cable services for SA to use.

The closest you can get is using SPF (supported in the upcoming SA 3.0), 
but that's up to the cable domain to create records for, and most don't.

SA can however determine if it's an illegitimate cable/dsl relay by using 
the dynamic-IP RBLs carefully (it does this already). No mailserver should 
*ever* be on a dynamic address, just because of the problems with having 
mail routing going to a constantly-changing IP address. In theory users 
with business-class static-address services shouldn't be in Dynablock.

Re: Can Spamassassin identify spam from DSL or Cable?

[Ryan Moore <ry...@perigee.net>]

Hou, Ming wrote:
> Hi,
> 
> I am using Spamassassin 2.63. I am wondering can Spamassassin determine 
> that the last hop of the mail relay is a legitimate DSL /Cable modem 
> mail server?  
> 
> Thanks,
> 
> ming
> 

I don't think there is anything that can determine if mail sent directly 
from a dynamic pool is legitimate (well not counting the overall SA 
score of the message). Most all email sent directly from dynamic pools 
to the destination MX are viruses/spam, and for that reason I block them 
at our border MTA via DNSBLs.


Ryan Moore
----------
Perigee.net Corporation
704-849-8355 (sales)
704-849-8017 (tech)
www.perigee.net