spam.his.com is doing an excellent job of blocking spam without stopping non-spam – the only false positives we’re seeing involve mail from bulk sources (overstock.com, alert.ema.dc.gov, etc., where many messages with the same content come in at once, which is characteristic of spam – you may find that you need to whitelist these if they’re winding up in your quarantine.
The system is also learning, as we’ve had time now to train it with feedback about what’s actually spam and not-spam – we update this Bayesian database daily, and this helps fine-tune filtering accuracy.
Two major improvements over Postini: little, if any, non-spam mail getting quarantined, and much faster reaction to new spam attacks that use new methods to get around filters. Barracuda updates its filters three times/hour, vs. once every day or two on Postini, and we’ve seen the effect of this in action – it works.
We’ve made a few minor changes – you’ll no longer see mail marked “?SPAM?” in your inbox. This was mail that Barracuda thought it might be spam but wasn’t sure so it didn’t quarantine it, but tagged it and passed it through. In practice, we found that as much non-spam as spam getting tagged, so this tagging wasn’t helpful and we’ve turned it off. These messages are still passed through, but without the tag.
Zimbra users: you have another layer of spam/virus/phishing filtering in Zimbra. Mail that Zimbra thinks is spam will be put in your Junk folder, and this is separate from what spam.his.com does. Check your Junk folder from time to time, and if any mail is there that isn’t spam, mark it as not-spam (you have to do this via webmail). Likewise, if any spam gets past spam.his.com and you find it in your inbox, you can mark it as spam. Zimbra’s spam filter learns from your feedback, and if you mark spam/not-spam for a week or two, its accuracy will improve. Zimbra’s spam filter works at the individual mailbox level, so you do need to train it so it knows whether you agree with what it’s doing.
If you want, you can forward spam that gets to your inbox to firstname.lastname@example.org – this will help them recognize new spam tricks and update their filters.
If you have any questions, open a support ticket by clicking “Open a Ticket” at http://info.his.com/support/support.his.com.html. Check our knowledgebase articles at https://support.his.com/kb/kb/browse/001925