Junk e-mail brings a scowl to just about every e-mailer's face. Spam stuffs PC downloads in-boxes full of obnoxious advertisements, adds precious minutes to download times, and worse, clogs businesses' and ISPs' mail servers and the Net.

What can be done against such a nasty foe? Nothing officially, despite the Videsh Sanchar Nigam Limited's protestations to the contrary. For now, only you can protect yourself from spam. Your weapon? Client-side spam-killing software. These applications work with your e-mail client to keep the lion's share of spam out of your in-box. They're cheap. And they're easily downloadable.

Two of the most popular spam-killers are SpammerSlammer and Spam Exterminator (SpamEx). Here's what they can and cannotdo, and how to use them.

SpammerSlammer's not only free, it's also a cinch to set up. Simply click the handy AutoConfig button to connect your e-mail client with Spammer, and from then on, all of your incoming e-mail will pass through SpammerSlammer.Both programmes comb messages for common spamming tricks, such as routing e-mail through several servers or using false reply-to names, then marks the guilty e-mail by putting SPAM in the subject header, followed by a number (one through five). The higher the number, the more likely it's spam.

The drawback? If an e-mail that you want happens to fit any one of SpamEx's spam criteria, it'll be deleted before create a filter in your e-mail client to route the spam to a special folder or directly to the trash. Since it automatically updates its tools you never see it. So, you'll need to spend extra time deactivating some of SpamEx's preset keyword filters and addresses to make sure it deletes only spam.

Both of the spam-killers are easy to set up, butSpammerSlammer requires less time and effort. Since you don't have to fiddle with its filters and rule sets, and since it automatically updates its tools when you're online, you'll spend less time getting SpammerSlammer up and running.

SpamEx may be worth the extra effort if you have a slow dial-up connection, since it erases messages before you download them. But most will prefer Spammer's simpler setup.

Spammer sits in the background and waits for spam, tagging suspect messages (SPAM appears in the subject header, followed by a number from one through five) just before they enter your in-box, making junk mail easy to filter in your e-mail client.

SpamEx, on the other hand, forces you to go through its preview window each time you check your mail, getting in the way of your standard e-mail routine. Some may appreciate the extra control the preview window provides, since it lets you decide which messages to download and which to trash right there on the server. But most people just want a hassle-freeway to make spam disappear, and SpammerSlammer is the program that delivers that convenience.

SpammerSlammer doesn't let you customize much. It does let you create your own filters; you can target e-mails with certain words in the subject header or messages from a particular addresses. And since it rates spam with the numbers one through five, you can easily filter spam via your e-mail client's filters, too. For instance, you can set a filter to dump e-mails labelled SPAM5 directly into the trash, and transfer e-mails labelled SPAM1 to a folder so you can check to make sure they're really spam. But besides these you create your own rules.

In tests run a leading US-based Internet consultancy firm, SpammerHammer caught 80 percent of the real-world spam. However, SpamEx stumbled where it really counts most for spam killers: accuracy. It killed only 53 percent of the real-world spam.

SpammerSlammer caught more than 25 percent more messages than Spam Exterminator did. With spammers creating ever moredeceptive techniques, merely filtering messages with common spam words in the subject header (as SpamEx does) is not enough. To really stop spam, you'll need a client that's hard to dupe, like SpammerSlammer.

It's easy to trick SpamEx; simply make the e-mail's subject line look respectable. But SpammerSlammer goes further than the subject line: it cleverly detects if a message has been rerouted or if it's been sent by a bulk e-mailer, which makes it quite difficult to fool.

The key to SpammerSlammer's success is its crafty spam-nabbing technique. Not only does it filter mail according to a proprietary list of keywords and return addresses (as SpamEx does), but it also looks for funny business in e-mail headers, checking the log of where the e-mail's been and when it was sent. The latter technique is great for catching spam, since most spammers try to send spam through many servers at different intervals in order to make the e-mail untraceable. Another huge plus: SpammerSlammer is free. Still, SpamEx mightbe for you if you're on a slow dial-up connection and want to kill spam before you've downloaded it to your computer. But its accuracy isn't great, and it costs $30.

And remember: neither of these spam killers works with proprietary mail protocols, such as those used by AOL and Prodigy. That's a pity, since users with proprietary accounts typically get the most spam.