E-mail systems are dynamic and can have a very variable architecture during communication. Sometimes important e-mails are unexpectedly Exchange Online may be marked as unwanted or spam by the email address, which results in emails landing in the junk folder instead of the inbox. This is an undesirable scenario for both the sender and the recipient.
When faced with situations like this, the best thing you can do as a recipient is to notify the sender and suggest they review their email infrastructure.
The sender must increase the security of their email servers and SPF, DKIM and DMARC must take the necessary steps to properly structure its records.
In fact, before getting into the topic, it is useful to state this; Domain Based Whitelisting should be the last scenario to be done, thus preventing spoofing emails from malicious email senders. EOP extension You will have given permission on it.
Exchange Online'in Domain Whitelist There are 2 methods to add as and the most reliable of these methods is Transport Rules is to privatize.
Adding Domain Whitelist Using Transport Rules in Exchange Online
Microsoft 365There are two main ways to whitelist a domain:
- Transport Rules
- Exchange Online Protection (EOP)
Other options include whitelisting the IP address or using the safe senders list in Outlook, but in this article we will focus on the “Tenant level domain whitelisting” process.
Let's start with the recommended method, Transport Rules. This method has the advantage of being able to add additional checks for the whitelist we added, for example DMARC We can include results or IP address check mechanisms.
- Playing Exchange Admin Center We log in on.
- "Mail FlowGo to the ” tab.
- "RulesClick on the ” section.
- Click on the plus (+) icon and select “Bypass Spam FilteringSelect ” option.
Give a name for the rule and “Apply this rule iffrom the "section"The Sender – Domain isSelect the ” option.
Enter the domain name you want to add. Let's use "cy.com.tr" as an example.
This whitelisting could result in malicious emails being delivered to your organization, so it is important to add additional conditions to this rule.
- "Add conditionClick the ” button.
- "Ip address is in any of these ranges or exactly matches” option and enter the IP address of the server or application that will send.
Other conditions we need to add: (These conditions are optional and you can change them according to your environment.
- "The Subject or Body > Subject includes any of these words“: You can filter incoming emails based on certain words in the subject line.
- "A Message header > includes any of these words" DMARC filtering and prevent address spoofing for a whitelisted domain.dmarc=passAdd the value ”.
As a final condition, “Set a message headerUse the ” option:
This, "X-ETRIt allows you to leave a flag when a message has bypassed spam filtering, using a header called “.
For example, "X-ETRBypass spam filtering for example.comYou can define a condition like “.
All conditions and whitelistAfter defining the domain address that needs to be imported, “SaveYou can complete the process with the " " button.
Adding Domain Whitelist Using Microsoft 365 Defender
There are several ways to whitelist a domain by logging into the Microsoft 365 Defender portal, but in this article we will focus on one of these methods. Although not the method Microsoft recommends, this process can be useful in some cases.
To the Microsoft 365 Defender portal https://security.microsoft.com You can access via this address.
To start the process, click on the "Policies & rules” and click on “Threat PoliciesGo to ” option. From here AntiSpam You can access their policies:
- Anti-Spam Policies Go to section.
- Among existing policies “Anti-Spam Inbound Policy” find the option.
- In the pop-up window “Edit allowed and blocked senders and domains” Click .
In this section, you can make changes to the allowed or banned users and domains. Since our aim is to add a domain as a whitelist “Allowed Domains” option and enter the domain name you want to allow and “Add DomainsClick the ” button.
Conclusion
This is how permission is granted using Microsoft 365 Domain Whitelist. However, to add more controls and conditions, Microsoft recommends Transport Rules It is recommended that you use the option.
