Secure Computing is advertising a free service that businesses can use to check on the volume of spam and malware emanating from hijacked PCs within domains owned by them.

Based on real-time information from the company’s TrustedSource reputation service, Domain Health Check, as it is called, supplies a “snapshot” rating for a domain. Domains that have compromised as relays for spam will obviously score poorly, but according to the company this fact will at least be obvious to the domain registrant.

A full four-page report contains enough detail to identify botnet zombies, phishing incidents that might have emanated from within particular domains, and spot fake or dormant email accounts.

Since the service is a free advert for the products with the Secure Computing range that use its reputation service technology, Domain Health Check also offers advice on dealing with any problems uncovered including, by implication, the possibility of buying Secure Computing or third-party products.

"TrustedSource is the most extensive Internet reputation system in the market and enables all of our gateway security appliances to accurately block malware, spam and phishing attacks at more than half the Fortune 500 companies," claimed Secure’s Atri Chatterjee.

"Domain Health Check provides this valuable information to anyone needing insight into the security of their websites and domains," he said.

Security companies agree that a record proportion of email is now spam, with some companies putting this as high as 90-95 percent of all traffic passing through anti-spam gateways. Despite an array of technologies put up to fight this, a small but pestering amount of spam is still managing to get through to desktops.

Secure Computing describes its own anti-spam and malware infrastructure thus: “With sensors in 51 countries, including 15 classifier machines and 20 TrustedSource real- time responders, TrustedSource scans billions of messages each month and blocks 6.2 TB of spam. It provides users with a 92 percent spam block rate, also blocking 83 percent of total mail volume well before spam reaches anti- spam filters. In addition, TrustedSource collects 100 GB of statistics daily.”

And yet even this can’t spot every spam source, so a reputation service built on a high but not perfect analysis of spam patterns is unlikely to give a complete view, critics would argue. The report is probably good only for identifying domains that have marked problems.

Recently, spammers have been using new techniques to trick anti-spam filters, while in January the so-called ‘Storm’ wormhit the Internet in the wake of a massive deluge of spam.