Topeka turns the tide on spam

Topeka, Kan., was being flooded, but not by water. Torrents of spam washed daily through the city's e-mail server.

'We were running about 800 pieces of spam per hour,' said Bill Stephens, Topeka's electronic communications manager. Of 1,000 Microsoft Outlook messages per hour, only 20 percent were legitimate.

'We don't want to pay workers to dig through the junk and throw it out,' Stephens said. 'We'd like to get to it before it reaches their desktops.'

So Topeka bought the P-Series Appliance from Proofpoint Inc. of Cupertino, Calif. Fitted on a 9-inch relay rack, the server appliance houses antivirus software from F-Secure Corp. of Helsinki, Finland.

The appliance examines each message for 57,000 spam attributes, assigning a spam probability of 0 to 100. ProofPoint's MLX machine learning technology is based on heuristics, Bayesian analysis and algorithms used in genomic sequencing. A ranking near 100 guarantees spam, Stephens said.

So far, the city has not had a problem with false positive scores for legitimate mail, Stephens said. He can assign specific attributes to look for, such as offensive words or a domain with a history of spamming. And the appliance isn't fooled by creative spellings of Viagra.

The average user 'doesn't even know about it,' Stephens said. But he can generate reports for users curious about their blocked mail.

The appliance also feeds a Web page where he can check statistics such as the number of messages per hour and the top spammers.

Topeka's 1,500 e-mail users have more confidence in the system now that the city has installed the antispam device, Stephens said, be-cause 'what's not getting through is stuff we don't want anyway.'

Spam is deleted after two weeks, although the time can be extended for someone who has missed an expected message.

So far the ProofPoint appliance still has 90 percent of its hard drive space free, Stephens said.

The appliance comes preconfigured with software. Stephens said he plugged it in, entered the IP address and other basic information, and within five minutes it was blocking spam.

Topeka plans to migrate to Microsoft Exchange Server 2003 by the end of the year.

About the Author

Trudy Walsh is a senior writer for GCN.


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