An SPF record is used to identify which mail servers (or systems) are allowed to send mail on your behalf. 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. Normally you use the -all element which indicates a hard fail. For example: Once you've formulated your SPF TXT record, follow the steps in Set up SPF in Microsoft 365 to help prevent spoofing to add it to your domain. In case we decide to activate this option, the result is that each of the incoming E-mails accepted by our Office 365 mail server (EOP), and that include SPF sender verification results of SPF = Fail, will automatically be marked as spam mail. office 365 mail SPF Fail but still delivered - Microsoft Community Hub We recommend the value -all. Customers on US DC (US1, US2, US3, US4 . ASF specifically targets these properties because they're commonly found in spam. Continue at Step 7 if you already have an SPF record. This option described as . To work around this problem, use SPF with other email authentication methods such as DKIM and DMARC. Why SPF Authentication Fails: none, neutral, fail (hard fail), soft In reality, most of the organization will not implement such a strict security policy because they would prefer to avoid a false-positive scenario in which a legitimate mail mistakenly identified as Spoof mail. SPF is configured by adding a specially formatted TXT record to the DNS zone for the domain. This type of configuration can lead us to many false-positive events, in which E-mail message that sent from our customer or business partner can be identified as spam mail. Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type. Also, if your custom domain does not have an SPF TXT record, some receiving servers may reject the message outright. However, over time, senders adjusted to the requirements. Also, if you're using DMARC with p=quarantine or p=reject, then you can use ~all. In each of the above scenarios, the event in which the SPF sender verification test ended with SPF = Fail result is not good. The SPF TXT record for Office 365 will be made in external DNS for any custom domains or subdomains. Although there are other syntax options that are not mentioned here, these are the most commonly used options. All SPF TXT records start with this value, Office 365 Germany, Microsoft Cloud Germany only, On-premises email system. This ASF setting is no longer required. In the current article, I want to provide you with a useful way, to implement a mail security policy related to an event in which the result of the SPF sender verification check is Fail. If we want to be more precise, an event in which the SPF sender verification test result is Fail, and the sender used the E-mail address, which includes our domain name. Messages that contain hyperlinks that redirect to TCP ports other than 80 (HTTP), 8080 (alternate HTTP), or 443 (HTTPS) are marked as spam. The three primary SPF sender verification test results could be: Regarding the result, in which the SPF result is Pass, this is a sign that we can be sure that the mail sender is a legitimate user, and we can trust this sender. You don't need to configure this setting in the following environments, because legitimate NDRs are delivered, and backscatter is marked as spam: In standalone EOP environments that protect inbound email to on-premises mailboxes, turning this setting on or off has the following result: More info about Internet Explorer and Microsoft Edge, Microsoft Defender for Office 365 plan 1 and plan 2. 01:13 AM We recommend that you disable this feature as it provides almost no additional benefit for detecting spam or phishing message, and would instead generate mostly false positives. Based on your mentioned description about "SPF authentication fails for our outbound emails sent by Exchange Online despite having this DNS record : v=spf1 include:spf.protection.outlook.com -all", once could you please provide us your detailed error message screenshot, your SPF record and domain via private message? A1: A Spoof mail attack implemented when a hostile element, uses a seemingly legitimate sender identity. You need all three in a valid SPF TXT record. In simple words, the destination recipient is not aware of a scenario in which the SPF result is Fail, and they are not aware of the fact that the E-mail message could be a spoofed E-mail. If you haven't already done so, form your SPF TXT record by using the syntax from the table. When this mechanism is evaluated, any IP address will cause SPF to return a fail result. It can take a couple of minutes up to 24 hours before the change is applied. Here is an example of an SPF record published on domain X, authorizing Office 365 to send emails on its behalf: For example, vs. the Exchange Online spam filter policy that marks every incoming E-mail message that has the value of SPF = Fail as spam mail without distinction, when using the option of Exchange rule, we can define a more refined version of this scenario, a condition in which only if the sender uses our domain name + the result from the SPF verification test is Fail, only, then the E-mail message will be identified as Spoof mail. There is no right answer or a definite answer that will instruct us what to do in such scenarios. Getting Started with PDQ Deploy & Inventory, Automatically assign licenses in Office 365, Match all domain name records (A and AAAA), Match all listed MX records. This tag allows plug-ins or applications to run in an HTML window. There are many free, online tools available that you can use to view the contents of your SPF TXT record. Mail forwards from Office 365 rejected due to SPF failure If an SPF TXT record exists, instead of adding a new record, you need to update the existing record. Microsoft Office 365. Enforcement rule is usually one of the following: Indicates hard fail. Each include statement represents an additional DNS lookup. To be able to use the SPF option we will need to implement by ourselves the following proceeds: Add to the DNS server that hosts our domain name the required SPF record, and verifies that the syntax of the SPF record is correct + verify that the SPF record includes information about all the entities that send an E-mail message on behalf of our domain name. For example, the company MailChimp has set up servers.mcsv.net. Some online tools will even count and display these lookups for you. Instead of immediately deleting such E-mail items, the preferred option is to redirect this E-mail to some isolated store such as quarantine. A typical SPF TXT record for Microsoft 365 has the following syntax: v=spf1 is required. How Sender Policy Framework (SPF) prevents spoofing - Office 365 Failed SPF authentication for Exchange Online - Microsoft Community This is because the receiving server cannot validate that the message comes from an authorized messaging server. However, there is a significant difference between this scenario. Messages that contain numeric-based URLs (typically, IP addresses) are marked as spam. In the current article series, our primary focus will be how to implement an SPF policy for incoming mail, by using the option of Exchange rule, and not by using the Exchange Online spam filter policy option. The meaning is a hostile element that executes spoofing or Phishing attacks and uses a sender E-mail address that includes our domain name. To be able to react to the SPF events such as SPF = none (a scenario in which the domain doesnt include a dedicated SPF record) or a scene of SPF = Fail (a scene in which the SPF sender verification test failed), we will need to define a written policy that will include our desirable action + configure our mail infrastructure to use this SPF policy.. For more information, see Advanced Spam Filter (ASF) settings in EOP. As you can see in the screenshot below, Microsoft has already detected an existing SPF record, marking it invalid.We can safely add include:spf.protection.outlook.com to our SPF record.In your DNS Hosting Provider, look up the SPF record, and click edit. Add include:spf.protection.outlook.com before the -all elementSo in this case it would be:v=spf1 ip4:213.14.15.20 include:servers.mcsv.net include:spf.protection.outlook.com -all. Include the following domain name: spf.protection.outlook.com. To defend against these, once you've set up SPF, you should configure DKIM and DMARC for Office 365. However, because anti-spoofing is based upon the From address in combination with the MAIL FROM or DKIM-signing domain (or other signals), it's not enough to prevent SRS forwarded email from being marked as spoofed. To be able to avoid from a false-positive event, meaning an event in which a legitimate E-mail message mistakenly identified as Spoof mail, I prefer more refinement actions such as send the E-mail to approval, send the E-mail to quarantine and so on. SPF configuration on exchange hybrid - Server Fault For example, Exchange Online Protection plus another email system. Select 'This page' under 'Feedback' if you have feedback on this documentation. SPF validates the origin of email messages by verifying the IP address of the sender against the alleged owner of the sending domain. By rewriting the SMTP MAIL FROM, SRS can ensure that the forwarded message passes SPF at the next destination. If you provided a sample message header, we might be able to tell you more. IP address is the IP address that you want to add to the SPF TXT record. Despite that the first association regarding the right response to an event in which the sender uses an E-mail address that includes our organization domain name + the result from the SPF sender verification test is fail, is to block and delete such E-mails; I strongly recommend not doing so. Notify me of followup comments via e-mail. Read Troubleshooting: Best practices for SPF in Office 365. To do this, contoso.com publishes an SPF TXT record that looks like this: When the receiving server sees this record in DNS, it also performs a DNS lookup on the SPF TXT record for contoso.net and then for contoso.org. SPF works best when the path from sender to receiver is direct, for example: When woodgrovebank.com receives the message, if IP address #1 is in the SPF TXT record for contoso.com, the message passes the SPF check and is authenticated. By looking at your SPF TXT record and following the chain of include statements and redirects, you can determine how many DNS lookups the record requires. LazyAdmin.nl also participates in affiliate programs with Microsoft, Flexoffers, CJ, and other sites. For more information, see Configure anti-spam policies in EOP. Q8: Who is the element which is responsible for alerting users regarding a scenario in which the result of the SPF sender verification test is Fail? Q9: So how can I activate the option to capture events of an E-mail message that have the value of SPF = Fail? For questions and answers about anti-spam protection, see Anti-spam protection FAQ. What happens to the message is determined by the Test mode (TestModeAction) value: The following Increase spam score ASF settings result in an increase in spam score and therefore a higher chance of getting marked as spam with a spam confidence level (SCL) of 5 or 6, which corresponds to a Spam filter verdict and the corresponding action in anti-spam policies. For example, create one record for contoso.com and another record for bulkmail.contoso.com. 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. adkim . SPF (Sender Policy Framework) is an email authorization protocol that checks the sender's IP address against a list of IPs published on the domain used as the Return-Path header of the email sent. For example, 131.107.2.200. [SOLVED] Office 365 Prevent Spoofing - The Spiceworks Community One drawback of SPF is that it doesn't work when an email has been forwarded. Default value - '0'. Required fields are marked *. Learn about who can sign up and trial terms here. What are the possible options for the SPF test results? If you don't have a deployment that is fully hosted in Microsoft 365, or you want more information about how SPF works or how to troubleshoot SPF for Microsoft 365, keep reading.