Altospam uses the authentication system only as a last resort. Anti-spam solutions based exclusively on sender authentication (also known as the Turing Test), which are supposedly 100% reliable, not only let spam through, but also generate a large number of false positives.
We believe that when used alone, this technology has a number of disadvantages:
– Transfer of filtering work to the message sender,
– Addition of a delay in mail delivery: a sender can send an email and be away for a long time, and only receive the authentication request on his return.
– Systematic sending of often unsolicited messages, which is a cause of false positives,
– It does not prevent 100% spam reception, as the identity of an authorized sender can be usurped by a spammer,
– It doesn’t address the problem of robots that aren’t necessarily spammers (for example, opening an incident on a hotline unknown to your system),
– Generates a very large number of emails (for authentication requests). These unsolicited emails are sometimes sent to senders whose email addresses have been spoofed,
– Finally, if a sender subscribes to another authentication-based anti-spam service, he will not receive the authentication request sent to him.
A service provider who guarantees 0% false positives and 100% blocked spam (0% false negatives) cannot be taken seriously. Who can claim to make any system 100% secure?