A mail from Michael Peddemors of linuxmagic.com made me look at a relative new and free DNSBL offering service – http://www.spamrats.com/

They offer 3 types of rbls viz.

1) RATS-Dyna (accessed via. ‘dyna.spamrats.com’) – This lists IPs which are known to make too many SMTP connections or trying too many invalid users and also IPs having rDNS entry which looks like it is a dynamic or home connection. Some IPs it blocked at my server were having rDNS as,
187-35-24-158.dsl.telesp.net.br
ppp-124-121-80-22.revip2.asianet.co.th
host84-240-dynamic.6-79-r.retail.telecomitalia.it

RATS-Dyna was listed as last rbl in my mail server after checking connections against having no rDNS, dnsbl-1.uceprotect.net and zen.spamhaus.org and it blocked surprisingly 10% more connections. In a way, it blocked 10% of probable spam which could have passed through other filters.

2) RATS-NoPtr (accessed via. ‘noptr.spamrats.com’) – This lists IPs which are known to make too many SMTP connections or trying too many invalid users and also IPs having no rDNS entry

What is use of RATS-NoPtr when most mail servers have inherent capability to reject IP with no rDNS entry. Michael Peddemors imply says “Performance actually, hard to believe ” and he might be right.

3) RATS-Spam (accessed via. ’spam.spamrats.com’) – This is an aggressive list and should be used with caution. This lists compromised servers, hosts, or open relays. Make sure you exempt your own customers from this list before using.
They say on their website – “RAT-Spam is better used in a scoring environment (like with spam assassin), rather than a blocking environment”.

For more spam stats see,
http://www.shantanukulkarni.org/rbl-compare.html
http://www.shantanukulkarni.org/spam_analysis.html

- tried implementing RBLs
But the issue was that roaming users had problems in sending mails using POP-before-SMTP services due to their IP being in RBLs.
- wrote custom filters for SA.
The result was good for sometime, but it was a time consuming process to write
rules and score them.
- trained bayes in SA feeding it with thousands of spam/ham.
Problem was like previous, worked good for a few days but the process had to be
continuous.
- started auto-learn for bayes training.
Somehow, with Bayes and especially with auto-learn, load average rose high.
- wrote a filter at delivery level, moving each mail above certain score to be
delivered to recipient’s “spam folder”.
Now, the inbox were a bit free but still spam folder was flooded with spam,
with some genuine mails lost in their depth.

But the spam just kept on coming …

Shantanu N Kulkarni

Read Tryst with spam – II

WHAT IS THIS SPAM, PLEASE STOP THAT SPAM!!! every other client of ours (the web hosting company in pune, India ) was complaining to us and asking IN CAPS what is this SPAM that is coming in the emails.. initially requesting us to stop the spam and later threatening us to take steps to stop SPAM. Little did i realise at that time that SPAM is not what is to be stopped but SPAM is what you EAT!!

SURPRISED ?? wait till you read the end if you dont know what is SPAM.

Well talking in the techbizpeople.com language.. spam actually refers to a mail sent to multiple email addresses whose owners have not asked for such emails. It is also referred to as bulk mail or junk mail and in WiKi language spam is unsolicited bulk e-mail (UBE) or “unsolicited commercial e-mail.”(UCE)

At Dimakh Consultants we fancied our stable mail servers and strong mailing solutions with very high up times of our servers. Our multiple servers which were managed by our support teams under Shantanu’s guidance were always performing to the best levels. But soon the problems started arising and then multiplying as everyday passed by. The support lines started ringing continuously, my mobile bill increased with more calls being made to shantanu’s residence number (at that time shantanu did not like mobiles so all calls were made to his residence number). I started spending more time in sorting the spam mails than responding to genuine mails. The servers stopped responding at crucial time(early mornings), the mails started getting lost in junk folders and clients complained of losing crucial mails and in turn business.

We read many stories of how spam is affecting a huge productive time worldwide, wasting a lot of the costly Internet bandwidth and some site also reported that they did a survey in USA in which they found that 17% of people or someone they knew had quit using e-mail because spam bothered them so much.

This was really an eye opener and we realised that URGENT steps had to be taken to avoid a catastrophe. Silent alarms were already raised from many of our important clients. They also encouraged us to find a good solution for which they were ready to pay and pay good!

So spam affected the technology, crippled the businesses and frustrated people.

We took this as a golden opportunity for a new business avenue and instead of reinventing the wheel decided to implement a tried and tested anti-spam solution for all our clients who were willing to pay extra to get the better solution and this helped us to stablilize the situation and in fact also earn new clients who were searching for a good anti-spam solution. The solution that we implemented was simple with DNSBL/RBL filtering so that we can block mails coming from known spammers and then additional steps to check virus, attachment filtering, content filtering etc. We also provide highest protection and medium protection levels where in highest protection only those mails would be passed which have been already authorized by the user and rest will be kept in queue till the user approves it or disapproves it. In medium protection level our strong algorithms at the backend to filtering and allow only selected mails to pass. our sales team would be more than happy to provide more details about this solution. do send an email to sales@dimakhconsultants.com

With additional steps taken by Shantanu we were able to get more clients for dedicated and customized mailing applications.

So that brings us to the conclusion and the answer to what is SPAM ?

SPAM is a registered trademark of Hormel Foods, LLC. (www.spam.com)
This is the one and only official SPAM Website, brought to you by the makers of the SPAM Family of products. All of the others have been created by somebody else.
Also, if the term is to be used, it should be used in all lower-case letters to distinguish it from our trademark SPAM, which should be used with all uppercase letters.