If you're using Proofpoint's spam filtering, you can whitelist KnowBe4 to allow our simulated phishing test emails and training notifications through to your end users.
The instructions below are for third-party software. If you run into issues whitelisting KnowBe4 in Proofpoint, we recommend reaching out to Proofpoint for specific instructions. You can also contact our support team whenever you need assistance.
If your phishing security test emails are bouncing with the following error message, see the How to Prevent Proofpoint from Bouncing Emails section of this article.
- "Sender address rejected: Domain not found (in reply to RCPT TO command)"
Whitelisting in Proofpoint
When you're ready to whitelist in Proofpoint, follow the below instructions. These instructions were gathered from Proofpoint's Safelisting Addresses article.
- Navigate to Security Settings > Email > Sender Lists.
- Under the Safe Sender list, enter our IP addresses. Please see our Whitelisting Data and Anti-Spam Filtering Information article for a full list of our IP addresses.
- Click Save.
If you have issues with attachment-related emails, see Proofpoint's article on Blocks by Default.
How to Prevent Proofpoint from Bouncing Emails
If some of your phishing security test (PST) emails are bouncing with an error message of
"Sender address rejected: Domain not found (in reply to RCPT TO command)",
follow the instructions below to resolve this issue.
- From your KnowBe4 console, click your email address in the top right corner and select Account Settings.
- Navigate to the Phishing Settings section.
- Check that the Overwrite Fixed Return-path Address with Sender Address option is not enabled (see below).
- Be sure to save this change by clicking the Save Changes button at the bottom of the page.
- To confirm this change will prevent Proofpoint from causing your PST emails to bounce, we recommend you test this change. You can do this by sending a test campaign to yourself or a limited number of users before sending it to a larger group.
What to Do If Your Emails are Going to Spam
If your emails are being sent to spam or are being quarantined, you'll need to add KnowBe4 to the Organizational Safe List in Proofpoint.
Follow the instructions below to add KnowBe4's hostnames or IP addresses to the Organizational Safe List:
- From your Proofpoint admin center, navigate to Email Protection > Spam Detection > Organizational Safe List.
- Add either our hostnames or IP addresses. For the most up-to-date list of our IP addresses and hostnames, please see this article.
Still need assistance? Submit a support ticket and we can help.