Viruses often spread via email, therefore it is important to virus scan emails before they arrive to the mailclient of the user. Perimeter actively blocks both spam AND viruses.
The far majority of email viruses are already blocked before they are scanned with our antivirus engine, thanks to our antispam technologies. Viruses generally try to spread similarly as spam emails, hence the antispam technologies block a large part of the viruses automatically and resource efficient. Thanks to this setup, even viruses not known yet to virusscanners are generally safely put in quarantine or rejected.
As an additional measure we are running the opensource ClamAV antivirus framework. The virus definitions are frequently updated (every 30 minutes). Besides the default ClamAV databases, we have added more datasets specialized in email virus outbreaks to ensure real-time and optimal protection again the latest virus outbreaks. Our internal reputation systems also contribute to the virus scanning part, and ensure optimal protection against not only spam, but also malware, phishing, and viruses.