What does SPF email authentication actually do? So before we can create the SPF record we first need to know which systems are sending mail on behalf of your domain, besides Office 365. As mentioned, in an Exchange-based environment, we can use the Exchange rule as a tool that will help us to capture the event of SPF = Fail and also, choose the required response to such an event. Your support helps running this website and I genuinely appreciate it. Continue at Step 7 if you already have an SPF record. @tsulaI solved the problem by creating two Transport Rules. SPF identifies which mail servers are allowed to send mail on your behalf. This improved reputation improves the deliverability of your legitimate mail. 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. These are added to the SPF TXT record as "include" statements. This conception is half true. I always try to make my reviews, articles and how-to's, unbiased, complete and based on my own expierence. Messages that use JavaScript or Visual Basic Script Edition in HTML are marked as high confidence spam. Legitimate newsletters might use web bugs, although many consider this an invasion of privacy. Although there are other syntax options that are not mentioned here, these are the most commonly used options. In Office 365 based environment (Exchange Online and EOP) beside the option of using Exchange rule, we can use an additional option the spam filter policy. Even when we get to the production phase, its recommended to choose a less aggressive response. Find out more about the Microsoft MVP Award Program. This option enables us to activate an EOP filter, which will mark incoming E-mail message that has the value of "SFP =Fail" as spam mail (by setting a high SCL value). The protection layers in EOP are designed work together and build on top of each other. SPF is designed to help prevent spoofing, but there are spoofing techniques that SPF can't protect against. Most of the time, I dont recommend executing a response such as block and delete E-mail that was classified as spoofing mail because the simple reason is that probably we will never have full certainty that the specific E-mail message is indeed spoofed mail. SPF helps validate outbound email sent from your custom domain (is coming from who it says it is). Also, if your custom domain does not have an SPF TXT record, some receiving servers may reject the message outright. A great toolbox to verify DNS-related records is MXToolbox. 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.. An SPF record is used to identify which mail servers (or systems) are allowed to send mail on your behalf. One of the options that can be activated is an option named SPF record: hard fail. By default, this option is not activated. Given that we are familiar with the exact structure of our mail infrastructure, and given that we are sure that our SPF record includes the right information about our mail servers IP address, the conclusion is that there is a high chance that the E-mail is indeed spoofed E-mail! Failing SPF will not cause Office 365 to drop a message, at best it will mark it as Junk, but even that wont happen in all scenarios. Here is an example of an SPF record published on domain X, authorizing Office 365 to send emails on its behalf: i check headers and see that spf failed. Q3: What is the purpose of the SPF mechanism? 01:13 AM Office 365 supports only one SPF record (a TXT record that defines SPF) for your domain. A good option could be, implementing the required policy in two phases-. Disable SPF Check On Office 365. Enforcement rule is usually one of the following: Indicates hard fail. - last edited on You will also need to watch out for the condition where you SPF record contains more than 10 DNS lookups, and take action to fix it when it happens. 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. You can only create one SPF TXT record for your custom domain. One option that is relevant for our subject is the option named SPF record: hard fail. On-premises email organizations where you route. If you set up mail when you set up Microsoft 365, you already created an SPF TXT record that identifies the Microsoft messaging servers as a legitimate source of mail for your domain. Go to your messaging server(s) and find out the External IP addresses (needed from all on-premises messaging servers). If you're using IPv6 IP addresses, replace ip4 with ip6 in the examples in this article. In this phase, we are only capturing event in which the E-mail address of the sender uses the domain name of our organization, and also; the result from the SPF sender verification test is Fail. This applies to outbound mail sent from Microsoft 365. Implement the SPF Fail policy using a two-phase procedure the learning/inspection phase and the production phase. When it finds an SPF record, it scans the list of authorized addresses for the record. and are the IP address and domain of the other email system that sends mail on behalf of your domain. Select 'This page' under 'Feedback' if you have feedback on this documentation. Most end users don't see this mark. 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. We recommend the value -all. Yes. In this article, I am going to explain how to create an Office 365 SPF record. Refresh the DNS records page in Microsoft 365 Admin Center to verify the settings.The status of the TXT record will be listed as Ok when you have configured it correctly. Gather this information: The SPF TXT record for your custom domain, if one exists. These tags are used in email messages to format the page for displaying text or graphics. Identify a possible miss configuration of our mail infrastructure. You can also specify IP address ranges using CIDR notation, for example ip4:192.168.0.1/26. Add a predefined warning message, to the E-mail message subject. If you provided a sample message header, we might be able to tell you more. By analyzing the information thats collected, we can achieve the following objectives: 1. In this phase, we will need to decide what is the concrete action that will apply for a specific E-mail message that will identify a Spoof mail (SPF = Fail). Take a look at the basic syntax for an SPF rule: For example, let's say the following SPF rule exists for contoso.com: v=spf1 . If you go over that limit with your include, a-records an more, mxtoolbox will show up an error! Go to Create DNS records for Office 365, and then select the link for your DNS host. 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. If you still like to have a custom DNS records to route traffic to services from other providers after the office 365 migration, then create an SPF record for . The SPF Record is structured in such a way that you can easily add or remove mail systems to or from the record. It's a first step in setting up the full recommended email authentication methods of SPF, DKIM, and DMARC. This is the default value, and we recommend that you don't change it. This article was written by our team of experienced IT architects, consultants, and engineers. This is reserved for testing purposes and is rarely used. We . If you haven't already done so, form your SPF TXT record by using the syntax from the table. However, the industry is becoming more aware about issues with unauthenticated email, particularly because of the problem of phishing. This record probably looks like this: If you're a fully hosted customer, that is, you have no on-premises mail servers that send outbound mail, this is the only SPF TXT record that you need to publish for Office 365. 0 Likes Reply If you're the sender's email admin, make sure the SPF records for your domain at your domain registrar are set up correctly. 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. This tag allows plug-ins or applications to run in an HTML window. Not every email that matches the following settings will be marked as spam. The E-mail address of the sender uses the domain name of a well-known bank. However, if you bought Office 365 Germany, part of Microsoft Cloud Germany, you should use the include statement from line 4 instead of line 2. LazyAdmin.nl is compensated for referring traffic and business to these companies at no expense to you. You will need to create an SPF record for each domain or subdomain that you want to send mail from. Attackers will adapt to use other techniques (for example, compromised accounts or accounts in free email services). The SPF Fail policy article series included the following three articles: Q1: How does the Spoof mail attack is implemented? You can read a detailed explanation of how SPF works here. Instead of immediately deleting such E-mail items, the preferred option is to redirect this E-mail to some isolated store such as quarantine. Q2: Why does the hostile element use our organizational identity? 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. However, over time, senders adjusted to the requirements. Anti-spoofing protection considers both SPF hard fails and a much wider set of criteria. 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. Need help with adding the SPF TXT record? 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). Links to instructions on working with your domain registrar to publish your record to DNS are also provided. Domain names to use for all third-party domains that you need to include in your SPF TXT record. Included in those records is the Office 365 SPF Record. This article describes how you form your SPF TXT record and provides best practices for working with the services in Microsoft 365. 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. If a message exceeds the 10 limit, the message fails SPF. Basically, SPF, along with DKIM, DMARC, and other technologies supported by Office 365, help prevent spoofing and phishing. SPF identifies which mail servers are allowed to send mail on your behalf. The SPF mechanism doesnt perform and concrete action by himself. is the domain of the third-party email system. You can only have one SPF TXT record for a domain. Also, if you're only using SPF, that is, you aren't using DMARC or DKIM, you should use the -all qualifier. The number of messages that were misidentified as spoofed became negligible for most email paths. In other words, using SPF can improve our E-mail reputation. When this setting is enabled, any message that hard fails a conditional Sender ID check is marked as spam. However, your risk will be higher. Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support. 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. Jun 26 2020 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) The reason that I prefer the option of Exchange rule is, that the Exchange rule is a very powerful tool that can be used to define a Tailor-made SPF policy that will suit the specific structure and the needs of the organization. This is because the receiving server cannot validate that the message comes from an authorized messaging server. TechCommunityAPIAdmin. There is no right answer or a definite answer that will instruct us what to do in such scenarios. Recipient mail systems refer to the SPF TXT record to determine whether a message from your custom domain comes from an authorized messaging server. Previously, you had to add a different SPF TXT record to your custom domain if you also used SharePoint Online. Indicates soft fail. 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. For advanced examples and a more detailed discussion about supported SPF syntax, see How SPF works to prevent spoofing and phishing in Office 365. 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? For example, let's say that your custom domain contoso.com uses Office 365. Periodic quarantine notifications from spam and high confidence spam filter verdicts. However, anti-phishing protection works much better to detect these other types of phishing methods. The SPF mechanism is not responsible for notifying us or, to draw our attention to events in which the result from the SPF sender verification test considered as Fail.. Some bulk mail providers have set up subdomains to use for their customers. If you have a hybrid deployment (that is, you have some mailboxes on-premises and some hosted in Microsoft 365), or if you're an Exchange Online Protection (EOP) standalone customer (that is, your organization uses EOP to protect your on-premises mailboxes), you should add the outbound IP address for each of your on-premises edge mail servers to the SPF TXT record in DNS. Do nothing, that is, don't mark the message envelope. 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. For example, contoso.com might want to include all of the IP addresses of the mail servers from contoso.net and contoso.org, which it also owns. Read Troubleshooting: Best practices for SPF in Office 365. The meaning is a hostile element that executes spoofing or Phishing attacks and uses a sender E-mail address that includes our domain name. There are many free, online tools available that you can use to view the contents of your SPF TXT record. See Report messages and files to Microsoft. Text. 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. And as usual, the answer is not as straightforward as we think. SPF sender verification test fail | External sender identity. 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. More info about Internet Explorer and Microsoft Edge, Microsoft Defender for Office 365 plan 1 and plan 2, Set up SPF in Microsoft 365 to help prevent spoofing, Troubleshooting: Best practices for SPF in Microsoft 365, Example: SPF TXT record for multiple outbound on-premises mail servers and Microsoft 365, Use DKIM to validate outbound email sent from your custom domain in Microsoft 365, Use DMARC to validate email in Microsoft 365, Create DNS records at any DNS hosting provider for Microsoft 365. The setting is located at Exchange admin Center > protection > spam filter > double click Default > advanced options > set SPF record: hard fail: off . This setting combines an SPF check with a Sender ID check to help protect against message headers that contain forged senders. What is the conclusion such as scenario, and should we react to such E-mail message? Secondly, if your user has the sender's address added to their safe senders list, or sender address is in contacts + contacts are trusted, the message would skip spam filtering and be delivered to inbox. The reason for our confidence that the particular E-mail message has a very high chance to consider as Spoof mail is because we are the authority who is responsible for managing our mail infrastructure. For information about the domains you'll need to include for Microsoft 365, see External DNS records required for SPF. After examining the information collected, and implementing the required adjustment, we can move on to the next phase. You can't report messages that are filtered by ASF as false positives. In this scenario, our mail server accepts a request to deliver an email message to one of our organization recipients. . It is true that Office 365 based environment support SPF but its imperative to emphasize that Office 365 (Exchange Online and EOP) is not configured anything automatically! Outlook.com might then mark the message as spam. adkim . First, we are going to check the expected SPF record in the Microsoft 365 Admin center. Test mode is not available for the following ASF settings: Microsoft 365 organizations with Exchange Online mailboxes. 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. What are the possible options for the SPF test results? 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. Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support. 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. An SPF TXT record is a DNS record that helps prevent spoofing and phishing by verifying the domain name from which email messages are sent. IP address is the IP address that you want to add to the SPF TXT record. You can list multiple outbound mail servers. Think of your scanners that send email to external contacts, (web)applications, newsletters systems, etc. Off: The ASF setting is disabled. Given that the SPF record is configured correctly, and given that the SPF record includes information about all of our organizations mail server entities, there is no reason for a scenario in which a sender E-mail address which includes our domain name will mark by the SPF sender verification test as Fail. Now that Enhanced Filtering for Connectors is available, we no longer recommended turning off anti-spoofing protection when your email is routed through another service before EOP. Scenario 2 the sender uses an E-mail address that includes. This is where we use the learning/inspection mode phase and use it as a radar that helps us to locate anomalies and other infrastructure security issues. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); LazyAdmin.nl is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com. Q5: Where is the information about the result from the SPF sender verification test stored? The simple truth is that we cannot prevent this scenario because we will never be able to have control over the external mail infrastructure that is used by these hostile elements. One option that is relevant for our subject is the option named SPF record: hard fail. We cannot be sure if the mail infrastructure of the other side support SPF, and if he implements an SPF sender verification test. Messages that contain numeric-based URLs (typically, IP addresses) are marked as spam. If an email message causes more than 10 DNS lookups before it's delivered, the receiving mail server will respond with a permanent error, also called a permerror, and cause the message to fail the SPF check. Q10: Why our mail server doesnt automatically block incoming E-mail that has the value of SPF = Fail? It can take a couple of minutes up to 24 hours before the change is applied. 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. Its Free. 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. We do not recommend disabling anti-spoofing protection. Domain administrators publish SPF information in TXT records in DNS. In case you wonder why I use the term high chance instead of definite chance is because, in reality, there is never 100% certainty scenario. For more information, see Advanced Spam Filter (ASF) settings in EOP. You add an SPF TXT record that lists the Office 365 messaging servers as legitimate mail servers for your domain. 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. Not all phishing is spoofing, and not all spoofed messages will be missed. ip4 indicates that you're using IP version 4 addresses. In case the mail server IP address that sends the E-mail on behalf of the sender, doesnt appear as authorized IP address in the SPF record, SPF sender verification test result is Fail. 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? ip6 indicates that you're using IP version 6 addresses. The SPF TXT record for Office 365 will be made in external DNS for any custom domains or subdomains. We can say that the SPF mechanism is neutral to the results his main responsibility is to execute the SPF sender verification test and to add the results to the E-mail message header. The meaning of the SPF = Fail is that we cannot trust the mail server that sends the E-mail message on behalf of the sender and for this reason, we cannot trust the sender himself. It's important to note that you need to create a separate record for each subdomain as subdomains don't inherit the SPF record of their top-level domain. When you have created a new Office 365 tenant and your subscription includes Exchange Online or Teams, then you will need to add a couple of DNS records. This is the scenario in which we get a clear answer regarding the result from the SPF sender verification test the SPF test fail! You do not need to make any changes immediately, but if you receive the "too many lookups" error, modify your SPF TXT record as described in Set up SPF in Microsoft 365 to help prevent spoofing. SPF record types were deprecated by the Internet Engineering Task Force (IETF) in 2014. The enforcement rule indicates what the receiving mail system should do with mail sent from a server that isnt listed in the SPF record. 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. Once you've formed your record, you need to update the record at your domain registrar. Some online tools will even count and display these lookups for you. 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. Use the 90-day Defender for Office 365 trial at the Microsoft 365 Defender portal trials hub. Although SPF is designed to help prevent spoofing, but there are spoofing techniques that SPF can't protect against. Also, the original destination recipient will get an E-mail notification, which informs him that a specific E-mail message that was sent to him was identified as Spoof mail and for this reason didnt automatically send to his mailbox. In our scenario, the organization domain name is o365info.com. We don't recommend that you use this qualifier in your live deployment. Office 365 supports only one SPF record (a TXT record that defines SPF) for your domain. In order to help prevent denial of service attacks, the maximum number of DNS lookups for a single email message is 10. When you want to use your own domain name in Office 365 you will need to create an SPF record. Basically, SPF, along with DKIM, DMARC, and other technologies supported by Office 365, help prevent spoofing and phishing. Despite my preference for using Exchange rule as preferred tool for enforcing the required SPF policy, I would also like to mention an option that is available for Office 365 customers, which their mail infrastructure based on Exchange Online and EOP (Exchange Online Protection). The second one reads the "Authentication-Results" line in the header information and if it says "Fail" sends the email to quarantine. Usually, this is the IP address of the outbound mail server for your organization. A4: The sender E-mail address, contains information about the domain name (the right part of the E-mail address). In each of the above scenarios, the event in which the SPF sender verification test ended with SPF = Fail result is not good.