Japan's NTT DoCoMo has unveiled new weapons in its war against junk e-mail

Japan's NTT DoCoMo has unveiled new weapons in its war against junk e-mail, or spam, on its popular wireless Internet service I-mode. The largest wireless Internet service of its kind with over 28 million subscribers, I-mode has been plagued by spam since it managed to sign up enough subscribers to attract unscrupulous marketers. The problem has enraged users who end up paying for the unwanted data downloaded in the junk marketing e-mail. Over the past year, DoCoMo has made efforts to curb the spam. The action has not been enough to satisfy its I-mode subscribers or deter spammers. On Tuesday, DoCoMo delved into its arsenal once more in an effort to put a stop to the nuisance. First, DoCoMo said it would attempt to block any e-mail that enters the I-mode system destined for a large number of "invalid" e-mail addresses. Large numbers of invalid e-mail addresses almost always mean the e-mail is being sent to a large range of possible e-mail addresses generated by the spammer via a simple software program. A genuine mail-out to people who requested the information would not contain such a large number of incorrect addresses. DoCoMo had to apply to Japan's Ministry of Public Management, Home Affairs, Posts and Telecommunications to have the measure approved. Blocking such e-mail also will prevent spammers from building genuine lists of I-mode e-mail addresses from the "user unknown" replies from invalid addresses.