Based on a spate of user accounts lock-outs caused by brute-force password guessing attempts using older protocols and to further enhance the security of our Hosted Exchange environment, we will be disabling:
- Authenticated SMTP Protocol
- Authenticated POP3 Protocol
- Authenticated IMAP Protocol
For the existing Exchange Mailboxes, this change will take place on or before July 30th, 2021.
The change will only be applied to users who do not currently connect to their Exchange Mailboxes via SMTP/POP3/IMAP according to the logs.
The vast majority of email clients now support modern protocols such as MAPI, EWS, and ActiveSync, and these provide a significantly higher level of security over the older SMTP POP3 and IMAP protocols.
For users that require these protocols, they can be enabled manually by a Celeratec technician.