today i received mail from my organization. Learn about who can sign up and trial terms here. 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. 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. 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. This allows you to copy the TXT value and also check if your domain already has an SPF record (it will be listed as Invalid Entry). You can only create one SPF TXT record for your custom domain. 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. 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. One of the options that can be activated is an option named SPF record: hard fail. By default, this option is not activated. Even when we get to the production phase, its recommended to choose a less aggressive response. Q3: What is the purpose of the SPF mechanism? 04:08 AM 01:13 AM and/or whitelist Messagelab (as it will not be listed as permitted sender for the domain you are checking): Office 365 Admin > Exchange admin center > protection > connection filter. For advanced examples and a more detailed discussion about supported SPF syntax, see How SPF works to prevent spoofing and phishing in Office 365. We . However, the industry is becoming more aware about issues with unauthenticated email, particularly because of the problem of phishing. This is no longer required. To be able to get a clearer view of the different SPF = Fail scenarios, lets review the two types of SPF = Fail events. 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. 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. The SPF TXT record for Office 365 will be made in external DNS for any custom domains or subdomains. 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. 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. Ensure that you're familiar with the SPF syntax in the following table. One option that is relevant for our subject is the option named SPF record: hard fail. The second one reads the "Authentication-Results" line in the header information and if it says "Fail" sends the email to quarantine. Basically, SPF, along with DKIM, DMARC, and other technologies supported by Office 365, help prevent spoofing and phishing. You then define a different SPF TXT record for the subdomain that includes the bulk email. Messages with no subject, no content in the message body, and no attachments are marked as high confidence spam. 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. A1: A Spoof mail attack implemented when a hostile element, uses a seemingly legitimate sender identity. If you have a hybrid configuration (some mailboxes in the cloud, and . You don't need to configure this setting in the following environments, because legitimate NDRs are delivered, and backscatter is marked as spam: In standalone EOP environments that protect inbound email to on-premises mailboxes, turning this setting on or off has the following result: More info about Internet Explorer and Microsoft Edge, Microsoft Defender for Office 365 plan 1 and plan 2. Off: The ASF setting is disabled. Attackers will adapt to use other techniques (for example, compromised accounts or accounts in free email services). Microsoft maintains a dynamic but non-editable list of words that are associated with potentially offensive messages. The SPF -all mechanism denotes SPF hardfail (emails that fail SPF will not be delivered) for emails that do not pass SPF check and is the recommended . In reality, the recipient will rarely access data stored in the E-mail message header, and even if they access the data, they dont have the ability to understand most of the information thats contained within the E-mail header. 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. The SPF information identifies authorized outbound email servers. 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. SPF, together with DKIM and DMARC helps to prevent spoofing of your mail domain. It doesn't have the support of Microsoft Outlook and Office 365, though. 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. 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. In each of the above scenarios, the event in which the SPF sender verification test ended with SPF = Fail result is not good. Indicates soft fail. Domain administrators publish SPF information in TXT records in DNS. - last edited on 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". 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. Add a new Record Select Type: TXT Name/Host: @ Content/Value: v=spf1 include:spf.protection.outlook.com -all (or copy paste it from Microsoft 365 ( step 4 )) Click SaveContinue at Step 8, If you already have an SPF record, then you will need to edit it. By rewriting the SMTP MAIL FROM, SRS can ensure that the forwarded message passes SPF at the next destination. 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. Suppose a phisher finds a way to spoof contoso.com: Since IP address #12 isn't in contoso.com's SPF TXT record, the message fails the SPF check and the receiver may choose to mark it as spam. 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). Messages that contain hyperlinks that redirect to TCP ports other than 80 (HTTP), 8080 (alternate HTTP), or 443 (HTTPS) are marked as spam. Solution: Did you try turning SPF record: hard fail on, on the default SPAM filter? Enforcement rule is usually one of the following: Indicates hard fail. A4: The sender E-mail address, contains information about the domain name (the right part of the E-mail address). When the receiving messaging server gets a message from joe@contoso.com, the server looks up the SPF TXT record for contoso.com and finds out whether the message is valid. Can we say that we should automatically block E-mail message which their organization doesnt support the use of SPF? You need all three in a valid SPF TXT record. 2. @tsulafirstly, this mostly depends on the spam filtering policy you have configured. . SPF is configured by adding a specially formatted TXT record to the DNS zone for the domain. An SPF record is a list of authorized sending hosts for the domain listed in the return path of an email. We recommend the value -all. An SPF record is used to identify which mail servers (or systems) are allowed to send mail on your behalf. 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. 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. Include the following domain name: spf.protection.outlook.com. In order to help prevent denial of service attacks, the maximum number of DNS lookups for a single email message is 10. If you have anti-spoofing enabled and the SPF record: hard fail ( MarkAsSpamSpfRecordHardFail) turned on, you will probably get more false positives. Received-SPF: Fail (protection.outlook.com: domain of mydomain.com does not designate 67.220.184.98 as permitted sender) receiver=protection.outlook.com; why spffailed mails normally received? A10: To avoid a scenario of false-positive meaning, a scene in which legitimate E-mail will mistakenly identify as a Spoof mail. A5: The information is stored in the E-mail header. 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.. 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. SPF discourages cybercriminals from spoofing your domain, spam filters will be less likely to blacklist it. is required for every domain and subdomain to prevent attackers from sending email claiming to be from non-existent subdomains. 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). If you're not sure that you have the complete list of IP addresses, then you should use the ~all (soft fail) qualifier. 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. 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. One option that is relevant for our subject is the option named SPF record: hard fail. Office 365 supports only one SPF record (a TXT record that defines SPF) for your domain. SPF identifies which mail servers are allowed to send mail on your behalf. 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. DMARC email authentication's goal is to make sure that SPF and DKIM information matches the From address. Microsoft Office 365. When this mechanism is evaluated, any IP address will cause SPF to return a fail result. The E-mail address of the sender uses the domain name of a well-known bank. 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. See Report messages and files to Microsoft. The rest of this article uses the term SPF TXT record for clarity. 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 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. There is no right answer or a definite answer that will instruct us what to do in such scenarios. Implement the SPF Fail policy using a two-phase procedure the learning/inspection phase and the production phase. Text. It can take a couple of minutes up to 24 hours before the change is applied. This is used when testing SPF. This article describes how you form your SPF TXT record and provides best practices for working with the services in Microsoft 365. 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! Your email address will not be published. Instead, ensure that you use TXT records in DNS to publish your SPF information. Read Troubleshooting: Best practices for SPF in Office 365. Email advertisements often include this tag to solicit information from the recipient. To defend against these, once you've set up SPF, you should configure DKIM and DMARC for Office 365. In our scenario, the organization domain name is o365info.com. For a list of domain names you should include for Microsoft 365, see External DNS records required for SPF. Anti-spoofing protection considers both SPF hard fails and a much wider set of criteria. And as usual, the answer is not as straightforward as we think. 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. In reality, most of the organization will not implement such a strict security policy because they would prefer to avoid a false-positive scenario in which a legitimate mail mistakenly identified as Spoof mail. . Other options are: I will give you a couple of examples of SPF records, so you have an idea of how they look when you combine different applications. The three primary SPF sender verification test results could be: Regarding the result, in which the SPF result is Pass, this is a sign that we can be sure that the mail sender is a legitimate user, and we can trust this sender. 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). Gather this information: The SPF TXT record for your custom domain, if one exists. 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. Specifically, the Mail From field that . 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. 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.