Oct 26th, 2018 at 10:51 AM. When this mechanism is evaluated, any IP address will cause SPF to return a fail result. This article was written by our team of experienced IT architects, consultants, and engineers. Here is an example of an SPF record published on domain X, authorizing Office 365 to send emails on its behalf: Unfortunately, no. For example, the company MailChimp has set up servers.mcsv.net. In this example, the SPF rule instructs the receiving email server to only accept mail from these IP addresses for the domain contoso.com: This SPF rule tells the receiving email server that if a message comes from contoso.com, but not from one of these three IP addresses, the receiving server should apply the enforcement rule to the message. Notify me of followup comments via e-mail. 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. 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). i check headers and see that spf failed. This tag allows plug-ins or applications to run in an HTML window. Ensure that you're familiar with the SPF syntax in the following table. A soft fail would look like this: v=spf1 ip4 192.xx.xx.xx ~all What Is SPF? - Sender Policy Framework Defined | Proofpoint US For advanced examples and a more detailed discussion about supported SPF syntax, see How SPF works to prevent spoofing and phishing in Office 365. 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. An SPF record is required for spoofed e-mail prevention and anti-spam control. Include the following domain name: spf.protection.outlook.com. We cannot be sure if the mail infrastructure of the other side support SPF, and if he implements an SPF sender verification test. [SOLVED] SPF Error when Sending an Email - MS Exchange The obvious assumption is that this is the classic scenario of Spoof mail attack and that the right action will be to block automatically or reject the particular E-mail message. When Microsoft enabled this feature in 2018, some false positives happened (good messages were marked as bad). To fix this issue, a sender rewriting scheme is being rolled out in Office 365 that will change the sender email address to use the domain of the tenant whose mailbox is forwarding the message. Read Troubleshooting: Best practices for SPF in Office 365. This tag is used to create website forms. @tsulafirstly, this mostly depends on the spam filtering policy you have configured. This ASF setting is no longer required. 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. Misconception 1: Using SPF will protect our organization from every scenario in which hostile element abuses our organizational identity. We recommend that you use always this qualifier. This conception is half true. One drawback of SPF is that it doesn't work when an email has been forwarded. For example, in case that we need to Impose a strict security policy, we will not be willing to take the risk, and in such scenario, we will block the E-mail message, send the E-mail to quarantine or forward the E-mail to a designated person that will need to examine the E-mail and decide if he wants to release the E-mail or not. Export the content of Exchange mailbox Recoverable items folder to PST using the Office 365 content search | Step by step guide | 2#3, Detect spoof E-mail and mark the E-mail as spam using Exchange Online rule | Part 4#12, Connecting users to their Exchange Online mailbox Stage migration solving the mystery | Part 2#2 | Part 36#36. 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. All SPF TXT records end with this value. ip4 indicates that you're using IP version 4 addresses. This applies to outbound mail sent from Microsoft 365. I am using Cloudflare, if you dont know how to change or add DNS records, then contact your hosting provider. 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. More info about Internet Explorer and Microsoft Edge. The meaning is a hostile element that executes spoofing or Phishing attacks and uses a sender E-mail address that includes our domain name. Even when we get to the production phase, its recommended to choose a less aggressive response. Gather this information: The SPF TXT record for your custom domain, if one exists. SPF = Fail but still delivered to inbox - Microsoft Community Hub In each of these scenarios, if the SPF sender verification test value is Fail the E-mail will mark as spam. 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. This is no longer required. Q3: What is the purpose of the SPF mechanism? Figure out what enforcement rule you want to use for your SPF TXT record. For example, create one record for contoso.com and another record for bulkmail.contoso.com. No. However, anti-phishing protection works much better to detect these other types of phishing methods. Some services have other, more strict checks, but few go as far as EOP to block unauthenticated email and treat them as spoofed messages. The element that should read this information (the SPF sender verification test result),and do something about it, is the mail server or the mail security gateway that represents the organization mail infrastructure. Use trusted ARC Senders for legitimate mailflows. You then define a different SPF TXT record for the subdomain that includes the bulk email. 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. 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 questions and answers about anti-spam protection, see Anti-spam protection FAQ. For example, if you are hosted entirely in Office 365, that is, you have no on-premises mail servers, your SPF TXT record would include rows 1, 2, and 7 and would look like this: The example above is the most common SPF TXT record. Messages that contain hyperlinks that redirect to TCP ports other than 80 (HTTP), 8080 (alternate HTTP), or 443 (HTTPS) are marked as spam. With a soft fail, this will get tagged as spam or suspicious. A1: A Spoof mail attack implemented when a hostile element, uses a seemingly legitimate sender identity. 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. More info about Internet Explorer and Microsoft Edge, Microsoft Defender for Office 365 plan 1 and plan 2, You don't know all sources for your email, Advanced Spam Filter (ASF) settings in EOP. 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. 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. and are the IP address and domain of the other email system that sends mail on behalf of your domain. 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. 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. 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. 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". However, the industry is becoming more aware about issues with unauthenticated email, particularly because of the problem of phishing. 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. GoDaddy, Bluehost, web.com) & ask for help with DNS configuration of SPF (and any other email authentication method). Mark the message with 'soft fail' in the message envelope. 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.. You can only create one SPF TXT record for your custom domain. Customers on US DC (US1, US2, US3, US4 . SPF record types were deprecated by the Internet Engineering Task Force (IETF) in 2014. 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.