Sharing best practices for building any app with .NET. Microsoft believes that the risk of continuing to allow unauthenticated inbound email is higher than the risk of losing legitimate inbound email. For a list of domain names you should include for Microsoft 365, see External DNS records required for SPF. Previously, you had to add a different SPF TXT record to your custom domain if you also used SharePoint Online. After a specific period, which we allocate for examining the information that collected, we can move on to the active phase, in which we execute a specific action in a scenario that the Exchange rule identifies an E-mail message that is probably Spoof mail. 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. 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. The SPF Fail policy article series included the following three articles: Q1: How does the Spoof mail attack is implemented? is the domain of the third-party email system. This ASF setting is no longer required. Next, see Use DMARC to validate email in Microsoft 365. As of October 2018, spoof intelligence is available to all organizations with mailboxes in Exchange Online, and standalone EOP organizations without Exchange Online mailboxes. One option that is relevant for our subject is the option named SPF record: hard fail. 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. This list is known as the SPF record. Q6: In case that the information in the E-mail message header includes results of SPF = Fail, does the destination recipient is aware of this fact? Included in those records is the Office 365 SPF Record. Great article. A3: To improve the ability of our mail infrastructure, to recognize the event in which there is a high chance, that the sender spoofs his identity or a scenario in which we cannot verify the sender identity.The other purpose of the SPF is to protect our domain mane reputation by enabling another organization to verify the identity of an E-mail message that was sent by our legitimate users. In our scenario, the organization domain name is o365info.com. I always try to make my reviews, articles and how-to's, unbiased, complete and based on my own expierence. In this scenario, we can choose from a variety of possible reactions.. SPF identifies which mail servers are allowed to send mail on your behalf. To do this, change include:spf.protection.outlook.com to include:spf.protection.outlook.de. You then define a different SPF TXT record for the subdomain that includes the bulk email. Your support helps running this website and I genuinely appreciate it. On-premises email organizations where you route. IT, Office365, Smart Home, PowerShell and Blogging Tips. You need some information to make the record. This is reserved for testing purposes and is rarely used. SPF helps validate outbound email sent from your custom domain (is coming from who it says it is). The enforcement rule indicates what the receiving mail system should do with mail sent from a server that isnt listed in the SPF record. In case we want to get more information about the event or in case we need to deliver the E-mail message to the destination recipient, we will have the option. When Microsoft enabled this feature in 2018, some false positives happened (good messages were marked as bad). 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. 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). 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. Summary: This article describes how Microsoft 365 uses the Sender Policy Framework (SPF) TXT record in DNS to ensure that destination email systems trust messages sent from your custom domain. 2. SPF sender verification test fail | External sender identity. Indicates neutral. Keep in mind, that SPF has a maximum of 10 DNS lookups. 0 Likes Reply 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. For advanced examples and a more detailed discussion about supported SPF syntax, see How SPF works to prevent spoofing and phishing in Office 365. For example, at the time of this writing, Salesforce.com contains 5 include statements in its record: To avoid the error, you can implement a policy where anyone sending bulk email, for example, has to use a subdomain specifically for this purpose. The receiving server may also respond with a non-delivery report (NDR) that contains an error similar to these: Some SPF TXT records for third-party domains direct the receiving server to perform a large number of DNS lookups. If you have a hybrid environment with Office 365 and Exchange on-premises. 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). SPF error with auto forwarding - Microsoft Community You will first need to identify these systems because if you dont include them in the SPF record, mail sent from those systems will be listed as spam. For questions and answers about anti-spam protection, see Anti-spam protection FAQ. Each SPF TXT record contains three parts: the declaration that it's an SPF TXT record, the IP addresses that are allowed to send mail from your domain and the external domains that can send on your domain's behalf, and an enforcement rule. SPF Hard Fail vs SPF Soft Fail | OnDMARC Help Center - Red Sift 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. Go to Create DNS records for Office 365, and then select the link for your DNS host. Normally you use the -all element which indicates a hard fail. Think of your scanners that send email to external contacts, (web)applications, newsletters systems, etc. For example, suppose the user at woodgrovebank.com has set up a forwarding rule to send all email to an outlook.com account: The message originally passes the SPF check at woodgrovebank.com but it fails the SPF check at outlook.com because IP #25 isn't in contoso.com's SPF TXT record. ASF specifically targets these properties because they're commonly found in spam. The reason for the outcome of SPF = Fail is related to a missing configuration on the sending mail infrastructure., The E-mail address of the sender, uses the domain name of, The result from the SPF sender verification test is , The popular organization users who are being attacked, The various types of Spoofing or Phishing attacks, The E-mail address of the sender includes our domain name (in our specific scenario; the domain name is, The result of the SPF sender verification check is fail (SPF = Fail). The main purpose of SPF is to serve as a solution for two main scenarios: A Spoof mail attacks scenario, in which hostile element abuses our organizational identity, by sending a spoofed E-mail message to external recipients, using our organizational identity (our domain name). 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. Can we say that we should automatically block E-mail message which their organization doesnt support the use of SPF? 04:08 AM Go to your messaging server(s) and find out the External IP addresses (needed from all on-premises messaging servers). A4: The sender E-mail address, contains information about the domain name (the right part of the E-mail address). SPF configuration on exchange hybrid - Server Fault This tag is used to create website forms. The presence of filtered messages in quarantine. 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. Most end users don't see this mark. Test mode is not available for this setting. Gather this information: The SPF TXT record for your custom domain, if one exists. The interesting thing is that in Exchange-based environment, we can use very powerful Exchange server feature named- Exchange rule, for identifying an event in which the SPF sender verification test result is Fail, and define a response respectively. Here is an example of an SPF record published on domain X, authorizing Office 365 to send emails on its behalf: Keeping track of this number will help prevent messages sent from your organization from triggering a permanent error, called a perm error, from the receiving server. For example, if you are hosted entirely in Office 365 Germany, that is, you have no on-premises mail servers, your SPF TXT record would include rows 1, 4, and 7 and would look like this: If you're already deployed in Office 365 and have set up your SPF TXT records for your custom domain, and you're migrating to Office 365 Germany, you need to update your SPF TXT record. 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. To get started, see Use DKIM to validate outbound email sent from your custom domain in Microsoft 365. SPF record types were deprecated by the Internet Engineering Task Force (IETF) in 2014. LazyAdmin.nl is compensated for referring traffic and business to these companies at no expense to you. The reason could be a problem with the SPF record syntax, a specific mail flow, such as E-mail forwarding that leads to this result, and so on. How to enforce SPF fail policy in Office 365 (Exchange Online) based environment, The main two purposes of using SPF mechanism, Scenario 1: Improve our E-mail reputation (domain name), Scenario 2: Incoming mail | Protect our users from Spoof mail attack, The popular misconception relating to SPF standard. All SPF TXT records start with this value, Office 365 Germany, Microsoft Cloud Germany only, On-premises email system. What are the possible options for the SPF test results? DKIM email authentication's goal is to prove the contents of the mail haven't been tampered with. The following examples show how SPF works in different situations. If you are a small business, or are unfamiliar with IP addresses or DNS configuration, call your Internet domain registrar (ex. Some services have other, more strict checks, but few go as far as EOP to block unauthenticated email and treat them as spoofed messages. This is the main reason for me writing the current article series. Select 'This page' under 'Feedback' if you have feedback on this documentation. To be able to send mail from Office 365 with your own domain name you will need to have SPF configured. What Is SPF? - Sender Policy Framework Defined | Proofpoint US The only thing that we can do is enable other organizations that receive an email message that has our domain name, the ability to verify if the E-mail is a legitimate E-mail message or not. Oct 26th, 2018 at 10:51 AM. The decision regarding the question, how to relate to a scenario in which the SPF results define as None and Fail is not so simple. The answer is that as always; we need to avoid being too cautious vs. being too permissive. Phishing emails Fail SPF but Arrive in Inbox - The Spiceworks Community SPF issue in Office365 with spoofing : r/Office365 - reddit How to Configure Office 365 SPF Record LazyAdmin