EOP includes a default spam filter policy, which includes various options that enable us to harden the existing mail security policy. Gather this information: The SPF TXT record for your custom domain, if one exists. Note: MailRoute will automatically recognize that you are using Office 365 for your outbound service, so you do not need to enter an outbound mailserver in the MailRoute Control Panel. Outlook.com might then mark the message as spam. [SOLVED] Office 365 Prevent Spoofing - The Spiceworks Community In many scenarios, the spoofed E-mail message will not be blocked even if the SPF value marked as Fail because of the tendency to avoid a possible event of false positives. Once you've formed your record, you need to update the record at your domain registrar. An SPF record is a DNS entry containing the IP addresses of an organization's official email servers and domains that can send emails on behalf of your business. IT, Office365, Smart Home, PowerShell and Blogging Tips. For example, 131.107.2.200. Below is an example of adding the office 365 SPF along with onprem in your public DNS server. In this step, we want to protect our users from Spoof mail attack. Use the step-by-step instructions for updating SPF (TXT) records for your domain registrar. All SPF TXT records start with this value, Office 365 Germany, Microsoft Cloud Germany only, On-premises email system. If you have a custom domain or are using on-premises Exchange servers along with Microsoft 365, you need to manually set up DMARC for your outbound mail. Edit Default > connection filtering > IP Allow list. A soft fail would look like this: v=spf1 ip4 192.xx.xx.xx ~all Login at admin.microsoft.com Navigate to your domain - Expand Settings and select Domains - Select your custom Domain (not the <companyname>.onmicrosoft.com domain Lookup the SPF Record Click on the DNS Records tab. DKIM email authentication's goal is to prove the contents of the mail haven't been tampered with. 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. ip4: ip6: include:. 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). Include the following domain name: spf.protection.outlook.com. 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 article describes how to update a Domain Name Service (DNS) record so that you can use Sender Policy Framework (SPF) email authentication with your custom domain in Office 365. 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. You can list multiple outbound mail servers. The -all rule is recommended. If you're already familiar with SPF, or you have a simple deployment, and just need to know what to include in your SPF TXT record in DNS for Microsoft 365, you can go to Set up SPF in Microsoft 365 to help prevent spoofing. In this category, we can put every event in which a legitimate E-mail message includes the value of SPF = Fail. Test mode is not available for this setting. 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. 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. If you're not sure that you have the complete list of IP addresses, then you should use the ~all (soft fail) qualifier. Some services have other, more strict checks, but few go as far as EOP to block unauthenticated email and treat them as spoofed messages. 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. This change should reduce the risk of SharePoint Online notification messages ending up in the Junk Email folder. The meaning of SPF =none is that a particular organization that is using a specific domain name doesnt support SPF or in other words, doesnt enable us to verify the identity of the sender that their E-mail message includes the specific domain name. Basically, SPF, along with DKIM, DMARC, and other technologies supported by Office 365, help prevent spoofing and phishing. This phase is described as learning mode or inspection mode because the purpose of this step has been just to identify an event of a Spoof mail attack in which the hostile element uses an E-mail address that includes our domain name + Log this information. 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. Required fields are marked *. This is the main reason for me writing the current article series. In scenario 1, in which the sender uses the identity of a well-known organization, we can never be sure definitively that the E-mail message is indeed a spoofed E-mail. See You don't know all sources for your email. Set up SPF to help prevent spoofing - Office 365 | Microsoft Learn 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. This is the default value, and we recommend that you don't change it. Test: ASF adds the corresponding X-header field to the message. The SPF Fail policy article series included the following three articles: Q1: How does the Spoof mail attack is implemented? 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. For example, create one record for contoso.com and another record for bulkmail.contoso.com. office 365 mail SPF Fail but still delivered Hello today i received mail from my organization. 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? 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. This is because the receiving server cannot validate that the message comes from an authorized messaging server. The element which needs to be responsible for capturing event in which the SPF sender verification test considered as Fail is our mail server or the mail security gateway that we use. 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. Jun 26 2020 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. The SPF TXT record for Office 365 will be made in external DNS for any custom domains or subdomains. 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. Instruct the Exchange Online what to do regarding different SPF events.. Usually, this is the IP address of the outbound mail server for your organization. The E-mail is a legitimate E-mail message. 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! To do this, change include:spf.protection.outlook.com to include:spf.protection.outlook.de. To be able to send mail from Office 365 with your own domain name you will need to have SPF configured. 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.. Learning/inspection mode | Exchange rule setting. Office 365 supports only one SPF record (a TXT record that defines SPF) for your domain. You can also specify IP address ranges using CIDR notation, for example ip4:192.168.0.1/26. Some online tools will even count and display these lookups for you. By rewriting the SMTP MAIL FROM, SRS can ensure that the forwarded message passes SPF at the next destination. There are many free, online tools available that you can use to view the contents of your SPF TXT record. In our scenario, the organization domain name is o365info.com. Mark the message with 'soft fail' in the message envelope. You will need to create an SPF record for each domain or subdomain that you want to send mail from. What is SPF? In order to protect against these, once you have set up SPF, you should also configure DKIM and DMARC for Microsoft 365. 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 6 commonly used elements in an SPF record are: You can add as many include: or ip4: elements to your SPF record as you need. Disabling the protection will allow more phishing and spam messages to be delivered in your organization. In some cases, like the salesforce.com example, you have to use the domain in your SPF TXT record, but in other cases, the third-party may have already created a subdomain for you to use for this purpose. 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). office 365 mail SPF Fail but still delivered, Re: office 365 mail SPF Fail but still delivered. 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. 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. However, over time, senders adjusted to the requirements. ip4 indicates that you're using IP version 4 addresses. 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. This tag allows plug-ins or applications to run in an HTML window. Read the article Create DNS records at any DNS hosting provider for Microsoft 365 for detailed information about usage of Sender Policy Framework with your custom domain in Microsoft 365.