Email Guardian is based on AMBAR, IberLayer AntiSpam patent pending Technology, that blocks junk email such as Spam, Phishing, ScamWare, etc. AMBAR can also block Marketing campaigns emails (also known as 'mass mailings' or mass email'), where the user supposedly has to click somewhere to unsubscribe and stop receiving those emails.
Nowadays there are Phishing campaigns extraordinarily well designed and constructed that can even cheat a well-trained user. This campaigns, admirable from the quality point fo view, often originate not on botnets but com hacked or compromised servers to maximize their impact.
Iberlayer Email Guardian has a language-independent phishing detection engine that protect customers against this threat, that in many cases does not pretend to steal user private date but to make user execute a dropper that will, sooner o later, download some Ransomware.
Email Guardian uses a combination of technologies aimed to have speedy delivery, so no greylisting!