I love technology. I am continually amazed by new technology, and I am constantly immersed in it. In fact, this was one of the main reasons that I started serve-you.net all those years back. Being that I am so involved in technology, my entire life now seems to be digital. If you are anything like me, email has nearly replaced snail mail for everything except packages. Just about the only things I get in the mail these days are bills and junk. It’s pretty easy to toss the junk in the recycle bin, or trash can. What about email? What is this SPAM, and what can we do about it?
Naturally, as people began to use email more and more, advertisers needed another way to get their message to people. Enter SPAM (unsolicited email). Over the years, the volume of SPAM has increased so rapidly, that it is now estimated to be responsible for over 90% of all email on the internet!
serve-you.net employs several different SPAM filtering techniques on the various servers that we manage, and we have varying levels of success keeping the SPAM away. The underlying program is the same on all, and that is spamassassin. spamassassin works by assigning a score to various items such as mail headers, keywords, HTML, etc. You set a threshold to what number you want to flag something as SPAM, and additionally can you can set another threshold to drop the messages completely.
One of the biggest problems anyone is faced with when doing SPAM filtering, is making sure that legitimate email doesn’t get flagged as SPAM. SPAMMERS have gotten craftier at making their messages harder to filter. Set your thresholds to high, and nothing ever gets flagged. Set them too low, and all kinds of legitimate mail gets flagged.
We’ve been tracking statistics on one of the domains that we host, and the numbers are definitely interesting. Their thresholds are somewhat aggressive, but still not quite enough to kill off any mail that they should really care about. So they are tagging at a score of 3, and dropping at a score of 7. Individual users may also have more or less aggressive rules on their own accounts, but most stick to that default setting.
This domain averages about 1500 emails/day. Of that, they are averaging a tag rate of around 16%, and a drop rate of around 42%. So that gives an average of 58% of their mail being SPAM. That’s an average of about 870 emails per day! And that’s just what was caught. From their comments, I’d estimate that another 10% of the mail that they received untagged, is also SPAM.