Email security appliances

Security appliances to protect mail servers against viruses and spam are all the rage. We look at what four of the leading vendors have to offer the medium-sized business.
Written by Alan Stevens, Contributor

There are lots of good reasons for considering a separate security appliance rather than running antivirus and spam filtering applications on a mail server. To start with, appliances are easier to install, with no compatibility or interoperability worries. And whereas add-on applications may adversely affect mail server performance, an independent appliance has no such impact. Indeed, by filtering out viruses and spam before they get to the server, overall throughput can be greatly enhanced.

What you get
The number of anti-virus/spam appliances has mushroomed lately, with solutions to handle mail servers of all sizes. All are based on industry-standard server hardware, typically running a security-hardened Unix/Linux OS to provide the platform for the mail-screening software.

Most of the time, the target mail server will be either Microsoft Exchange or Lotus Notes -- although that’s not a prerequisite, and any SMTP mail server can be used. Indeed, in most cases all you have to do to do is forward port 25 (SMTP) traffic to the appliance address. In some cases DNS changes may also be required, but most can be up and running in just a few minutes.

Management is via a browser, with tools to monitor activity and manage the antivirus/spam rules, custom black/white lists and other filtering options. Blocked or quarantined messages can also be examined via the GUI with some products allowing end users to do this themselves.

What we tested
We looked at four products aimed at medium-sized businesses. All provided the same basic tools to screen out viruses and block spam, mostly using well known software. However, only two were able to filter outgoing as well as incoming mail; the products from Barracuda and Tumbleweed could only handle incoming messages.

All four appliances are designed to keep themselves up to date and, in terms of their ability to trap viruses and block spam, there wasn’t a great deal to choose between them. They did, however, vary considerably on configuration and management, from the ridiculously easy Tumbleweed MailGate 2.2, with hardly any options, to the Barracuda, which was stuffed full of them.

The MailGate appliance also lets users manage their own black/white lists and quarantined messages and, because of its simplicity, it’s a good choice for the smaller company with limited technical resources. For the larger organisation, however, an appliance that allows greater control over the filtering process is preferable. In this respect the Barracuda Spam Firewall is hard to beat, and we recommend it if you only want inbound filtering. Otherwise, the more expensive RazorGate has the most to offer, including its unique MailHurdle technology with which you can really slam the door in the face of spammers.

Email security appliances compared

Barracuda Spam Firewall 400

Mirapoint RazorGate 100

SurfControl RiskFilter E-mail E10

Tumbleweed MailGate 2.2

Format 1U rackmount 1U rackmount 1U rackmount 1U rackmount
Processor AMD Athlon 64 XP 2400 2.4GHz Intel Xeon 2.8GHz Intel Pentium 4 3.06GHz Intel Pentium 4
Disk space 320GB 40GB 68GB 72GB
Network interfaces 1 x 10/100Mbps 2 x 10/100Mbps (1 for admin) 1 x 10/100Mbps 1 x 10/100Mbps
Operating system Linux Unix Linux Linux
Virus scanning yes yes yes yes (optional)
Antivirus engine proprietary Sophos McAfee McAfee and/or Kaspersky
Spam filtering yes yes yes yes
Spam engine SpamAssassin SpamAssassin (CommTouch from end of 2004) SurfControl proprietary
Mail security features
Outbound filtering no optional yes no
Email disclaimers no yes yes no
Proxy POP3 server no yes yes no
Proxy IMAP server no yes yes no
Proxy HTTP server no yes yes no
Per-user black/white lists yes end of 2004 yes yes
User quarantine control yes end of 2004 yes yes
Price (ex. VAT)
First year £3,885 £4,500 £8,500 £4,000
Number of users unlimited 100 500 1,000
Subsequent annual costs £873 (Energizer updates) £500 (100 users) 50% of purchase price 20% of purchase price

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