Can we say that we should automatically block E-mail message which their organization doesnt support the use of SPF? However, there are some cases where you may need to update your SPF TXT record in DNS. 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! Although SPF is designed to help prevent spoofing, but there are spoofing techniques that SPF can't protect against. The -all rule is recommended. For more information, see Example: SPF TXT record for multiple outbound on-premises mail servers and Microsoft 365. domain name is the domain you want to add as a legitimate sender. The Exchange incident report includes a summary of the specific mail flow, such as the name of the sender, recipient, and the Exchange rule that was activated and also; we can ask to include an attachment of the original E-mail message that was captured.. For questions and answers about anti-spam protection, see Anti-spam protection FAQ. LazyAdmin.nl also participates in affiliate programs with Microsoft, Flexoffers, CJ, and other sites. This is implemented by appending a -all mechanism to an 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? Default value - '0'. Scenario 1. Include the following domain name: spf.protection.outlook.com. For information about the domains you'll need to include for Microsoft 365, see External DNS records required for SPF. The E-mail is a legitimate E-mail message. All SPF TXT records start with this value, Office 365 Germany, Microsoft Cloud Germany only, On-premises email system. From my experience, the phase is fascinating because after we activate the monitor process, we will usually find an absorbing finding of: Based on this information, we will be able to understand the real scope of the problem, the main characters of this attack and so on. Fix Your SPF Errors Now SPF Check Path The path for the check is as follows Exchange Admin Center > Protection > Spam Filter > Double Click Default > Advanced Options > Set SPF record: Hard fail: Off One of the prime reasons why Office 365 produces a validation error is an invalid SPF record. Join the movement and receive our weekly Tech related newsletter. The SPF mechanism doesnt perform and concrete action by himself. Included in those records is the Office 365 SPF Record. This ASF setting is no longer required. 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. Below is an example of adding the office 365 SPF along with onprem in your public DNS server. However, over time, senders adjusted to the requirements. Indicates neutral. For example, 131.107.2.200. For example, Exchange Online Protection plus another email system. Basically, SPF, along with DKIM, DMARC, and other technologies supported by Office 365, help prevent spoofing and phishing. When you want to use your own domain name in Office 365 you will need to create an SPF record. Test mode is not available for the following ASF settings: Microsoft 365 organizations with Exchange Online mailboxes. SPF helps validate outbound email sent from your custom domain (is coming from who it says it is). Customers on US DC (US1, US2, US3, US4 . If you've already set up mail for Office 365, then you have already included Microsoft's messaging servers in DNS as an SPF TXT record. The setting is located at Exchange admin Center > protection > spam filter > double click Default > advanced options > set SPF record: hard fail: off. Q9: So how can I activate the option to capture events of an E-mail message that have the value of SPF = Fail? When Microsoft enabled this feature in 2018, some false positives happened (good messages were marked as bad). If you have any questions, just drop a comment below. Some bulk mail providers have set up subdomains to use for their customers. This list is known as the SPF record. 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. However, there is a significant difference between this scenario. If it finds another include statement within the records for contoso.net or contoso.org, it will follow those too. 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. 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. This tool checks your complete SPF record is valid. Even in a scenario in which the mail infrastructure of the other side support SPF, in case that the SPF verification test marked as Fail, we cannot be sure that the spoofed E-mail will be blocked. 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. This option combines an SPF check with a Sender ID check to help protect against message headers that contain forged senders. My opinion that blocking or rejecting such E-mail messages is too risky because, we cannot enforce other organizations to use SPF, although using SPF is recommended and help to protect the identity and the reputation of a particular domain. Microsoft Office 365. If all of your mail is sent by Microsoft 365, use this in your SPF TXT record: In a hybrid environment, if the IP address of your on-premises Exchange Server is 192.168.0.1, in order to set the SPF enforcement rule to hard fail, form the SPF TXT record as follows: If you have multiple outbound mail servers, include the IP address for each mail server in the SPF TXT record and separate each IP address with a space followed by an "ip4:" statement. To do this, change include:spf.protection.outlook.com to include:spf.protection.outlook.de. 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. This type of scenario, there is a high chance that we are experiencing a Spoof mail attack! 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. The Exchange tool/option that we use for the purpose of gathering information about a particular mail flow event is described as an incident report. The SPF sender verification can mark a particular E-mail message with a value to SPF = none or SPF = Fail. No. . This is reserved for testing purposes and is rarely used. SPF determines whether or not a sender is permitted to send on behalf of a domain. Need help with adding the SPF TXT record? In this scenario, our mail server accepts a request to deliver an email message to one of our organization recipients. For more information, see Advanced Spam Filter (ASF) settings in EOP. Messages with no subject, no content in the message body, and no attachments 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 . Disable SPF Check On Office 365. Use the 90-day Defender for Office 365 trial at the Microsoft 365 Defender portal trials hub. 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 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. In order to protect against these, once you have set up SPF, you should also configure DKIM and DMARC for Microsoft 365. Make sure that you include all mail systems in your SPF record, otherwise, mail sent from these systems will be listed as spam 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. It's a first step in setting up the full recommended email authentication methods of SPF, DKIM, and DMARC. 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. Messages that contain words from the sensitive word list in the subject or message body are marked as high confidence spam. SRS only partially fixes the problem of forwarded email. 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. Sender Policy Framework, or SPF, is an email authentication technique that helps protect email senders and recipients from spam, phishing and spoofing. There is no right answer or a definite answer that will instruct us what to do in such scenarios. Setting up DMARC for your custom domain includes these steps: Step 1: Identify valid sources of mail for your domain. For tips on how to avoid this, see Troubleshooting: Best practices for SPF in Microsoft 365. For example, let's say that your custom domain contoso.com uses Office 365. 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. 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 Microsoft 365 Admin Center only verifies if include:spf.protection.outlook.com is included in the SPF record. This scenario can have two main clarifications: A legitimate technical problem a scene in which we are familiar with the particular mail server/software component, that sent an email message on behalf of our domain, A non-legitimate mail element a scenario in which we discover that our organization uses mail server or mail applications that send an E-mail message on behalf of our domain, and we are now aware of these elements.. Office 365 supports only one SPF record (a TXT record that defines SPF) for your domain. TechCommunityAPIAdmin. Think of your scanners that send email to external contacts, (web)applications, newsletters systems, etc. Did you know you can try the features in Microsoft 365 Defender for Office 365 Plan 2 for free? Use one of these for each additional mail system: Common. Notify me of followup comments via e-mail. Anti-spam message headers includes the syntax and header fields used by Microsoft 365 for SPF checks. In the next article, Implementing SPF Fail policy using Exchange Online rule (dealing with Spoof E-mail attack) | Phase 1 learning mode | Part 2#3, we will review the step-by-step instruction needed to create an Exchange Online rule that will help us to monitor such events. Hope this helps. You can read a detailed explanation of how SPF works here. There are many free, online tools available that you can use to view the contents of your SPF TXT record. I am using Cloudflare, if you dont know how to change or add DNS records, then contact your hosting provider. If you have a hybrid configuration (some mailboxes in the cloud, and some mailboxes on premises) or if you're an Exchange Online Protection standalone customer, add the outbound IP address of . 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). 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. In addition to IP addresses, you can also configure your SPF TXT record to include domains as senders. Text. office 365 mail SPF Fail but still delivered Hello today i received mail from my organization. If you are a small business, or are unfamiliar with IP addresses or DNS configuration, call your Internet domain registrar (ex. 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. This will avoid the rejections taking place by some email servers with strict settings for their SPF checks. 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. SPF enables receiving mail servers to authenticate whether an email message was sent from an authorized mail server - but only when the domain owner's SPF record is valid. 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. 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) We will review how to enable the option of SPF record: hard fail at the end of the article. In this step, we want to protect our users from Spoof mail attack. Conditional Sender ID filtering: hard fail. For each ASF setting, the following options are available in anti-spam policies: On: ASF adds the corresponding X-header field to the message, and either marks the message as Spam (SCL 5 or 6 for Increase spam score settings) or High confidence spam (SCL 9 for Mark as spam settings). 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. Messages that contain web bugs are marked as high confidence spam. SPF identifies which mail servers are allowed to send mail on your behalf. 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. 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. 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. 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 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. A typical SPF TXT record for Microsoft 365 has the following syntax: text v=spf1 [<ip4>|<ip6>:<IP address>] [include:<domain name>] <enforcement rule> For example: text v=spf1 ip4:192.168..1 ip4:192.168..2 include:spf.protection.outlook.com -all where: v=spf1 is required. 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. SPF, together with DKIM and DMARC helps to prevent spoofing of your mail domain.