Libra ESVA 2 review
Libra is new to the UK and its ESVA (email security virtual appliance) offers an impressive arsenal of messaging security measures at a very low price. It uses a 13-step spam and virus detection process and claims to have a high success rate.
ESVA is delivered as an OVF file. Libra also has an image for Microsoft’s Virtual PC, which is only for evaluation purposes. It will be supporting Microsoft’s Hyper-V early in 2011.
After downloading the OVF file, we deployed it as a template to our ESX Server 4 system and had a new VM with the appliance loaded on it in minutes.
The main web console provides spam statistics for the current week and valuable information about the VM swap file status and disk usage. A table shows the day’s activity, while a pie chart provides a breakdown of clean messages, spam and infections.
An unusual feature is the local RBL, which is created using data from ESVA’s own anti-spam engine. Any IP address it thinks is sending too much spam during this period will be automatically blocked.
There’s support for Active Directory and Exchange. Only direct LDAP server queries are made by the appliance, so it doesn’t cache passwords locally. The anti-spam engine scores suspect messages as ham or spam and the thresholds for these can be modified.
You can decide to quarantine, block, forward, delete or bounce messages, strip out HTML content and tag their subject lines. Plenty more controls are provided, and clean messages can be delivered normally, tagged and have any HMTL content converted to text.
Attachment filtering is basic. You can’t create lists of file extensions to block and can only exclude a single email address from attachment scanning.
The message content protection (MCP) feature scans 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.
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: after a week, it returned a 99.3% success rate against live spam. False-positives were also low: over the entire testing period only eight messages were incorrectly identified as spam and placed in the quarantine area.
There may be plenty of virtual anti-spam appliances on the market, but ESVA stands out with its easy deployment on VMware and its range of security and anti-spam measures. Spam detection rates are high, you don’t need to know anything about Linux to configure it, and it’s particularly good value.
|Software subcategory||Internet security|