ITS Service Desk

How does whitelisting work?

Occasionally a campus department will take on a project where an outside company will need to send an email to SNC people. Sometimes that email is going to only students, sometimes it's directed at employees, and other times it's directed at all of us. When this happens, the vendor often asks you to have your IT department whitelist their email servers to insure their email does not get filtered as spam. So let's talk about why a whitelist is needed and how it works.

Who controls our Inbox?

The first thing to understand is that as email users, we have great control over what lands in our Inbox and of course great control over what we read. Therefore, no level of whitelisting can guarantee that an email ends up in a person's Inbox, much less that the person will read it.

The best way to make sure an email is not marked as spam is to send email that doesn't look like spam. It's imperative that any vendor who sends email as part of their services to the college also understands this. And if they do understand it and their email doesn't look like spam, then there's really no need for whitelisting.


We've seen situations first hand where a student didn't receive an email, even though we've whitelisted the sending email server. Again, this is because the user has significant control over their Inbox. Google doesn't disclose their Gmail spam filtering algorithms, but it's reasonable to assume that even when we whitelist a server, an email shouldn't get through to the recipient if they just don't want it. And we can't force them to want it.

As an example, if a user chooses not to receive emails about surveys, they might consistently mark all such emails as spam, which of course causes future survey emails to go directly into their spam folder. Then, if you (or a vendor) send them an email with a survey, you should expect that the email will go to that user's spam folder, whether we whitelist the server or not, especially if the user has setup their own filters. After all, if a survey email lands in a recipient's Inbox and they dislike survey emails, they won't be too keen to read what you have to say.


All of that said, whitelisting can still help, especially for users who really don't care what they receive in their Inbox. But, let's be clear: whitelisting an email server is only needed when you think your incoming email would normally be flagged as spam. And it's certainly no guarantee that all of your recipients will read your message.

If you'd like us to consider adding a server to our whitelist, please send your request to us at

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