Sendmail: How does one blacklist annoying spammers?

[Daniel B. Thurman]

On 06/27/2010 10:06 AM, Craig White wrote:
> On Sun, 2010-06-27 at 09:45 -0700, Daniel B. Thurman wrote:
>   
>> On 06/27/2010 07:56 AM, Genes MailLists wrote:
>>     
>>> On 06/26/2010 07:57 PM, Daniel B. Thurman wrote:
>>>
>>>   
>>>       
>>>> THANKS!  I have implemented the above recommendations
>>>> as well as a few other advices in this posting.
>>>>
>>>> Thanks to all who participated - all very interesting to
>>>> know how others have tackled the their spam issues.
>>>>
>>>> I will report how it all goes for me as I was getting at least
>>>> 250 spam messages a day... it was getting on my nerves :/
>>>>
>>>>
>>>>     
>>>>         
>>>   I hope this helps for you ... for me these + careful access controls
>>> works well.
>>>
>>>
>>>   A good access file, well managed is very helpful too ... for
>>> blacklisting, for whitelisting, for 0s greet pause for known mx'ers etc.
>>>
>>>
>>>   Hope you cut down some of your spam .. :-)
>>>
>>> gene
>>>   
>>>       
>> It's a bit early, but so far, I have received two spams... pretty
>> good so far, but I will report back in a couple more days...
>>
>> I wanted to mention that there are some in this posting that
>> are recommending greylisting...  but have not said anything
>> about how this is implemented into sendmail... so, what is
>> your take on this?
>>     
> ----
> you could actually do some research - information is easy to find
>
> http://www.greylisting.org
>
> Craig
>
>   
Thanks for the tip!  I will review greylisting.

On the greylisting.org site, there seems to be a number of GL-milter
implementations for sendmail. Also, there is a GL-milter available
on Fedora... I wonder what the consensus is for which is, for the
best of, or more popular of GL-milter implementations.

In review of Evan Harris's whitepaper (2003),  he seems to imply
(or point out) that whitelisting is not a good idea because if spammers
ever discover what is on your whitelist (how, I do not know), they could,
at least in theory bypass greylists....  Well, I need to review some more
to make sure I fully understand the pros and cons and the necessary
steps to make it work properly before attempting to do so.  I am a
bit fuzzy still, as if a whitelist needs to be filled in, what exactly
should
go into it....  more research  I guess...

I am not yet sure if what I have for now is sufficient for my tastes
(i.e. I am not yet using greylisting) and Spamhaus and "Gene's MailList"
seems to cut back a LOT of spams so far...

Interesting, though, & thanks again,
Dan