Plenty more controls are provided as clean messages can be delivered normally, tagged and have any HMTL content converted to text. You can also store all messages in the appliance's quarantine area although we found this fills up very quickly so is best turned off.
Attachment filtering is very basic as you can't create lists of file extensions you want to block and can only declare a single email address that is exempted from attachment scanning. However, Libra advised us that this is one of the features in its to-do list for the next release.
The MCP (message content protection) feature attempts to prevent unwanted data leaks by scanning for keywords in message subjects and body content and assigns high or low scores to each message. You can adjust the scoring system and apply all the same message controls as for spam.
Configuring MCP takes a little practise as you use SQL queries. However, Libra provides some basic help in the web interface and it wasn't long before we were able to create quite complex expressions and successfully apply them to inbound and outbound mail.
To test spam detection rates we allowed the appliance to scan live email and left it on its default scoring settings. All ham and spam was passed to the quarantine area so we could easily see false positives and checking our mail clients allowed us to see if any dodgy messages had slipped through.
ESVA impressed as after a week it returned a 99.3 per cent success rate against live spam. False positives were also low as over the entire testing period only eight messages were incorrectly identified as spam and placed in the quarantine area.
SMBs looking for a virtual anti-spam appliance should consider ESVA which has a fine combination of features and performance. Libra has done a good development job with its intuitive web interface, so you don't need to to know any Linux, and the very affordable pricing structure.
Verdict
We were impressed with Libra ESVA as it delivered excellent anti-spam performance in our live tests. The software is very easy to deploy and configure and although we had some criticisms these are likely to be rectified in future versions. Libra’s low prices also make ESVA a worthy choice for SMBs looking to virtualise their network security services.
SYSTEM REQUIREMENTS OS: VMware Server/ESX/ESXi. For evaluation only - VMware Workstation/Player; Microsoft Virtual PC Memory: 1GB unreserved RAM Hard disk: 20-40GB free space
