Instituto Superior Técnico

Serviços de Informática

Spam prevention systems

The email service includes an anti-spam global filter global to the Técnico email. The emails flagged by that filter with an high probability of being spam are automatically moved to a “SPAM” folder (or equivalent) in the user’s mailbox. Because false positives are possible we advise you to check this folder periodically or when some expected email seems to be missing.

Furthermore, to avoid abuse of the email service, there are limits to the number of emails (recipients) that can be sent in a set period of time. The limits are checked for intervals of 5 minutes, 1 hour and 1 day. The IT service will attempt to keep those limits as high as possible compatible with the need to avoid the blacklisting of the email servers.

When a user triggers one of the limits, that will be explained in the error message received by the user. If the daily limit is reached the account will be prevented from sending email for 24h (from the first emails that were counted towards the limit). Before this daily limit is reached the 5 minutes and 1 hour limits will be triggered, so there should be sufficient warning to avoid it.

When sending a large number of emails is necessary the mailing lists service should be used.