Over the past few days, a number of Sheridan users have reported that email they have sent to outside organizations or individuals is being returned. Unfortunately, this was occurring because Sheridan’s email domain had been blacklisted by a number of internet spam tracking services. Currently, Sheridan’s email domain has been removed from the blacklists.
How Did Sheridan Get on the Blacklist?
Sheridan’s email domain was added to a blacklist as a result of a compromised account that was sending spam email messages. Individuals receiving the spam messages reported the abuse and, consequently, Sheridan’s email servers were blacklisted. I.T. disabled the account quickly, but the damage had already been done.
How Do We Get Off the Blacklist?
Getting off a blacklist is not straightforward or easy. There are a number of spam monitoring services and blacklists. Each blacklist has its own procedures for requesting removal, and we can only request removal from the blacklists we know that we’re on. It may take some time before the “reputation” of our email domain is completely restored. Please be patient.
Report Bounce Backs
If you receive a return email like the example above, it is critical that you forward the message to abuse@sheridanc.on.ca so we can work with the appropriate party to have Sheridan removed from their list.
Automatic Expiry
In some cases, offending servers/domains are automatically removed from a blacklist after a certain period of time – typically about five days.
Vigilance and Prevention
Again, please be vigilant of the email messages that land in your inbox – especially phishing messages that ask you to divulge personal information. Sheridan will NEVER send you an email asking you to divulge account details, or with links asking you to log into your account. The easiest way to protect yourself is to never respond to anyone who asks for personal information by email; even it is from a seemingly legitimate source.
When in doubt contact infosec@sheridanc.on.ca for a second opinion.