IntY's MailDefender manages to squeeze quite a lot of mail filters and controls into an attractive and uncomplicated interface. We might have preferred the default first screen to be the useful quarantine summary (giving customer-wide mail totals), rather than the actual quarantining itself, but this was just a minor quibble.
We were pleased to see that new user accounts (including the default administrator account provided by intY) are assigned complicated default passwords. That was somewhat undermined by a plaintext login from which we were able to easily capture credentials.
Granularity is excellent – all the settings can be configured on a per user basis if you need that degree of control – but we were disappointed with the lack of options for importing an external user list or managing groups.
From the quarantine, mail can be specifically tagged to train the Bayesian spam filters.
IntY uses a number of technologies to classify spam, including two separate Bayesian filters, URL checks against a list of known spam sites, the open source SpamAssassin engine, several RBLs and character-set blocks.
Only the Bayesian and SpamAssassin options were enabled by default. Most of these can be adjusted for weighting, and each message processed by the service is given custom X-Header fields which explain how its score was calculated.
The service's junk message detection rate was very good, but lacking a "test mode" we were unable to evaluate the filters without risking a relatively high false positive rate. This is a problem we have had with IntY before, and while we still miss the lack of a testing mode, the false positive rate was markedly better than before.
The service uses Sophos for anti-virus checks, and we would like to see at least one other AV product used in parallel (IntY tells us ClamAV is to be rolled out in 2005).
The service also felt slow – both the interface and email processing were sluggish. Sometimes, only a slight lag was evident, but at other times we were frustrated by the lack of response.