Postini tunes e-mail threat protection

Claiming that "content filtering by itself is bankrupt" as a means of protection, Postini focuses on transport-layer e-mail intrusion prevention. The company runs a managed service for its customers to protect enterprise servers and desktops at the perimeter, stopping spam and viruses before they enter the network. Directory harvest and denial of service attacks are stopped at the SMTP (port 25) connection.

Perimeter Manager 5.0 includes enhanced connection management and IP analysis and uses dynamic and cross-correlated blacklisting capabilities. Improved IP whitelisting provides a global list of IP addresses that are "well behaved" and unlikely to send spam, helping to reduce quarantining of false positives.

Postini has also added a "blatant spam" blocking option in which spam that is rated above a certain threshold is rejected outright and not even quarantined, reducing the quarantine load.

Improvements have been made to the administrator interface and to search functions, bulk change management, and quarantine management.

The company said that an average implementation requires only an MX redirect and takes about three days. The managed service is targeted at organizations of 100 or more users. Pricing varies from $6 to $30 per user, depending on the extent of service and the number of users, with a minimum order of $2,500.