We are going to start with looking up the DNS records that Microsoft 365 is expecting and then add the correct SPF record to our DNS hosting provider: First, we are going to check the expected SPF record in the Microsoft 365 Admin center. A hard fail, for example, is going to look like this: v=spf1 ip4 192.xx.xx.xx -all If mail is being sent from another server that's not the IP in the SPF, the receiving server will discard it. In reality, there is always a chance that the E-mail message in which the sender uses our domain name includes and the result from the SPF sender verification test is Fail could be related to some miss configuration issue. Best thing to do is report the message via the Junk add-in and open a support case to have it properly investigated. For example, 131.107.2.200. We reviewed the need for completing the missing part of our SPF implementation, in which we need to capture an event of SPF sender verification test in which the result is fail and, especially, in a scenario in which the sender E-mail address includes our domain name (most likely certainly a sign that this is a Spoof mail attack). Office 365 supports only one SPF record (a TXT record that defines SPF) for your domain. Update your SPF TXT record if you are hitting the 10 lookup limit and receiving errors that say things like, "exceeded the lookup limit" and "too many hops". Also, if you're only using SPF, that is, you aren't using DMARC or DKIM, you should use the -all qualifier. Legitimate newsletters might use web bugs, although many consider this an invasion of privacy. SRS only partially fixes the problem of forwarded email. In reality, the recipient will rarely access data stored in the E-mail message header, and even if they access the data, they dont have the ability to understand most of the information thats contained within the E-mail header. v=spf1 ip4:10.10.10.1/16 mx ptr:Sender.domain.com include:spf.protection.outlook.com ~all. A2: The purpose of using the identity of one of our organization users is because, there is a high chance that the Innocent victim (our organization user), will tend to believe someone he knows vs. some sender that he doesnt know (and for this reason tends to trust less). Select 'This page' under 'Feedback' if you have feedback on this documentation. The SPF TXT record for Office 365 will be made in external DNS for any custom domains or subdomains. Email advertisements often include this tag to solicit information from the recipient. As mentioned, in this phase our primary purpose is to capture Spoof mail attack events (SPF = Fail) and create a log which will be used for analyzing the information thats gathered. As mentioned, the SPF sender verification test just stamp the E-mail message with information about the SPF test result. You can also specify IP address ranges using CIDR notation, for example ip4:192.168.0.1/26. Domain administrators publish SPF information in TXT records in DNS. The answer is that as always; we need to avoid being too cautious vs. being too permissive. A wildcard SPF record (*.) The following examples show how SPF works in different situations. Add a predefined warning message, to the E-mail message subject. office 365 mail SPF Fail but still delivered, Re: office 365 mail SPF Fail but still delivered. A great toolbox to verify DNS-related records is MXToolbox. This tool checks your complete SPF record is valid. We don't recommend that you use this qualifier in your live deployment. For questions and answers about anti-spam protection, see Anti-spam protection FAQ. In reality, we can never be sure in 100%, that the E-mail message is indeed spoofed E-mail message or, a legitimate E-mail message. Mark the message with 'hard fail' in the message envelope and then follow the receiving server's configured spam policy for this type of message. This setting combines an SPF check with a Sender ID check to help protect against message headers that contain forged senders. SPF is added as a TXT record that is used by DNS to identify which mail servers can send mail on behalf of your custom domain. Gather the information you need to create Office 365 DNS records, Troubleshooting: Best practices for SPF in Office 365, How SPF works to prevent spoofing and phishing in Office 365, Common. Follow us on social media and keep up with our latest Technology news. The organization publishes an SPF record (implemented as TXT record) that includes information about the IP address of the mail servers, which are authorized to send an E-mail message on behalf of the particular domain name. Go to Create DNS records for Office 365, and then select the link for your DNS host. For advanced examples, a more detailed discussion about supported SPF syntax, spoofing, troubleshooting, and how Office 365 supports SPF, see How SPF works to prevent spoofing and phishing in Office 365. 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) Mark the message with 'soft fail' in the message envelope. is the domain of the third-party email system. For example, in an Exchange Online based environment, we can activate an Exchange Online server setting that will mark each E-mail message that didnt pass the SPF verification test (SPF = fail) as spam mail. For example, we are reasonable for configuring SPF record that will represent our domain and includes the information about all the mail server (the Hostname or the IP address) that can send E-mail on behalf of our domain name. For each ASF setting, the following options are available in anti-spam policies: On: ASF adds the corresponding X-header field to the message, and either marks the message as Spam (SCL 5 or 6 for Increase spam score settings) or High confidence spam (SCL 9 for Mark as spam settings). A soft fail would look like this: v=spf1 ip4 192.xx.xx.xx ~all Default value - '0'. Q5: Where is the information about the result from the SPF sender verification test stored? SPF is the first line of defense in this and is required by Microsoft when you want to use a custom domain instead of the onmicrosoft.com domain. Messages sent from an IP address that isn't specified in the SPF Sender Policy Framework (SPF) record in DNS for the source email domain are marked as high confidence spam. Once a message reaches this limit, depending on the way the receiving server is configured, the sender may get a message that says the message generated "too many lookups" or that the "maximum hop count for the message has been exceeded" (which can happen when the lookups loop and surpass the DNS timeout). Messages that use JavaScript or Visual Basic Script Edition in HTML are marked as high confidence spam. 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. For example: Having trouble with your SPF TXT record? This can be one of several values. To be able to get a clearer view of the different SPF = Fail scenarios, lets review the two types of SPF = Fail events. The following Mark as spam ASF settings set the SCL of detected messages to 9, which corresponds to a High confidence spam filter verdict and the corresponding action in anti-spam policies. To defend against these, once you've set up SPF, you should configure DKIM and DMARC for Office 365. i check headers and see that spf failed. Some online tools will even count and display these lookups for you. If you do not use any external third-party email services and route all your emails via Office 365, your SPF record will have the following syntax: v=spf1 include:spf.protection.outlook.com -all. Instead of immediately deleting such E-mail items, the preferred option is to redirect this E-mail to some isolated store such as quarantine. If you don't use a custom URL (and the URL used for Office 365 ends in onmicrosoft.com), SPF has already been set up for you in the Office 365 service. Some bulk mail providers have set up subdomains to use for their customers. If the sender isn't permitted to do so, that is, if the email fails the SPF check on the receiving server, the spam policy configured on that server determines what to do with the message. . For example in Exchange-based environment, we can add an Exchange rule that will identify SPF failed events, and react to this type of event with a particular action such as alert a specially designated recipient or block the E-mail message. I always try to make my reviews, articles and how-to's, unbiased, complete and based on my own expierence. This is because the receiving server cannot validate that the message comes from an authorized messaging server. DKIM email authentication's goal is to prove the contents of the mail haven't been tampered with. Figure out what enforcement rule you want to use for your SPF TXT record. Otherwise, use -all. ASF specifically targets these properties because they're commonly found in spam. For example, let's say that your custom domain contoso.com uses Office 365. Creating multiple records causes a round robin situation and SPF will fail. Conditional Sender ID filtering: hard fail. Included in those records is the Office 365 SPF Record. If you have a hybrid configuration (some mailboxes in the cloud, and . Exchange Online (EOP), include spam filter policy, which contains many security settings that are disabled by default and can be activated manually based on the particular mail security policy that the organization wants to implement. Learn about who can sign up and trial terms here. In addition to IP addresses, you can also configure your SPF TXT record to include domains as senders. Note: Suppose we want to be more accurate, this option is relevant to a scenario in which the SPF record of the particular domain is configured with the possibility of SPF hard fail. However, there is a significant difference between this scenario. This is reserved for testing purposes and is rarely used. In order to protect against these, once you have set up SPF, you should also configure DKIM and DMARC for Microsoft 365. Required fields are marked *. @tsulafirstly, this mostly depends on the spam filtering policy you have configured. Another distinct advantage of using Exchange Online is the part which enables us to select a very specific response (action), that will suit our needs such as Perpend the E-mail message subject, Send warning E-mail, send the Spoof mail to quarantine, generate the incident report and so on. The defense action that we will choose to implement in our particular scenario is a process in which E-mail message that identified as Spoof mail, will not be sent to the original destination recipient..