In case that your organization experiences a scenario in which your mail server IP address, In the current article and the next article: My E-mail appears as spam | Troubleshooting, In the current article, we will review how to deal with Spoof mail by creating, Your email address will not be published. The setting is located at Exchange admin Center > protection > spam filter > double click Default > advanced options > set SPF record: hard fail: off . Read Troubleshooting: Best practices for SPF in Office 365. This list is known as the SPF record. If the receiving server finds out that the message comes from a server other than the Office 365 messaging servers listed in the SPF record, the receiving mail server can choose to reject the message as spam. An SPF record is used to identify which mail servers (or systems) are allowed to send mail on your behalf. A9: The answer depends on the particular mail server or the mail security gateway that you are using. Login at admin.microsoft.com Navigate to your domain - Expand Settings and select Domains - Select your custom Domain (not the <companyname>.onmicrosoft.com domain Lookup the SPF Record Click on the DNS Records tab. In order to use a custom domain, Office 365 requires that you add a Sender Policy Framework (SPF) TXT record to your DNS record to help prevent spoofing. Feb 06 2023 SPF Record Check | SPF Checker | Mimecast Also, if your custom domain does not have an SPF TXT record, some receiving servers may reject the message outright. This type of mail threat appears in two flavors: In this section, I would like to review a couple of popular misconceptions that relate to the SPF standard. Suppose a phisher finds a way to spoof contoso.com: Since IP address #12 isn't in contoso.com's SPF TXT record, the message fails the SPF check and the receiver may choose to mark it as spam. Received-SPF: Fail (protection.outlook.com: domain of mydomain.com does not designate 67.220.184.98 as permitted sender) receiver=protection.outlook.com; why spffailed mails normally received? i check headers and see that spf failed. Hope this helps. This is because the receiving server cannot validate that the message comes from an authorized messaging server. This article provides frequently asked questions and answers about anti-spoofing protection for Microsoft 365 organizations with mailboxes in Exchange Online, or standalone Exchange Online Protection (EOP) organizations without Exchange Online mailboxes. Authentication-Results: spf=none (sender IP is 118.69.226.171) smtp.mailfrom=kien.ngan; thakrale5.onmicrosoft.com; dkim=none (message not signed) header.d=none;thakrale5.onmicrosoft.com; dmarc=none action=none header.from=thakrale5.onmicrosoft.com; Received-SPF: None (protection.outlook.com: kien.ngan does not designate permitted sender hosts)