Nepali Times
Spam, spammer, spammest


When, of the six new emails in your inbox, four are advertising everything from home mortgages to cheap Viagra, it seems like ISPs should do more about unsolicited mail (aka spam). But, perhaps surprisingly, there are actually some measures in place to stop the clutter. Considering half of all emails an ISP receives are junk, your inbox could easily be in even worse shape.

Currently, most Nepali ISPs, including Mercantile, Worldlink and Infocom, use an online database called the Realtime Blackhole List (RBL). As mails come through, the sender addresses are checked against the RBL database, which lists known spam mailers and filters out emails from these senders. Unfortunately, this can lead to some legitimate mails (called 'false negatives' in industry jargon) being dumped as well.

There are similar problems with SpamAssassin, the other major spam control method currently in use. This software is meant to automatically identify spam on the basis of some characteristic features of junk mails, such as headers that try to make it seem like a valid email, and style, keywords and disclaimers in the text. The program also uses spam-tracking databases and blacklists of spam senders. Currently, Worldlink uses this program, and Mercantile is likely to start soon.

It is also possible for individual users to install email filters to block junk mail. Often, these are permission-based tools, which only allow emails from addresses included in your address book or on a 'whitelist' to reach your inbox. This can be tricky though, because if you occasionally receive unexpected email that you want to get, blocking every unknown server won't work. A new type of filtering, called challenge/response, or CR, remedies this problem. When an email comes in from an unknown sender, the CR tool responds with a message asking the sender to perform some action, such as clicking a link. Virtually all spam mailers generally use fake email addresses, and so never respond, and therefore only people sending genuine emails get past the filter.

Instead of just depending on your ISP or filters, there are a few things you can do to prevent and reduce spam. Avoid posting your email address online. Often sites will ask for your address so they can send you updates or to include you in forums, message boards and newsgroups. Spammers use automated systems to search these sources, or sometimes the sites themselves sell lists to someone looking for valid email addresses. Spammers can also get addresses off emails that have been forwarded, which often accumulate hundreds of email addresses.

The smartest thing is to not pass on forwarded messages, and ask your friends not to send them to you either. However, if you feel it is important to pass on the message, you can cut and paste the relevant text and only pass that on, instead of the original mail with all the accumulated addresses. Entering your friend's email addresses in the bcc line (blank carbon copy) will help protect your friends against spam, as their email address will not appear in the message even if they send it to other people.

Binaya Joshi, system administrator at Mercantile, has a final piece of advice: don't respond to spam mail in any way, especially clicking on the 'unsubscribe' link that many spammers try to trick you with. Spam mailing lists often contain inactive or nonexistent email addresses, so by responding, it is like confirming that you have an active account, making it likely you'll get even more spam.

Bhushan Shilpakar is the Nepali Times web master, and will not post his email address here for fear of spammers.

(11 JAN 2013 - 17 JAN 2013)