Internet Security Systems is joining the packed email security market with a new product that claims to block both spam and viruses while also preventing intrusion.

The Proventia Network Mail Security System will be available later this month and is designed to sit at an enterprise's gateway to block malicious email plus prevent sensitive information from getting out.

Despite the intrusion prevention add-on, ISS enters an already overcrowded market that is starting to mature and shake out. Many companies have already placed their bets on the vendors they believe will survive.

ISS will go up against Barracuda, CipherTrust, IronPort, Mirapoint, Proofpoint and others. The company argued that because it offers products in other security areas - unlike many of its competitors - organisations will want to standardise on ISS.

The Proventia Network Mail appliance blocks spam, viruses, worms, phishing attacks and other malicious code attempting to enter a system through email. It includes ISS' existing Virus Prevention System, which examines the behaviour of network traffic to detect viruses before signature matches are released for them, said its marketing head Dave Ostrouski. The company also offers Sophos' anti-virus technology as an add-on.

The product applies keyword matching to outbound email messages so companies can ensure employees aren't sending out information protected by regulation or corporate policy, Ostrouski says. The Proventia Network Mail Security System appliance costs $20,300 and can support up to 2,500 users.