You need to create a sender policy framework (SPF) record for the e-mail servers on your network.
Which type of resource record should you create?
A.
Alias (CNAME)
B.
Host Information (HINFO)
C.
Signature (SIG)
D.
Text (TXT)
Explanation:
Authenticating Outbound E-Mail:
Domain holders need to complete an inventory and publish all IP addresses of their outbound e-mail servers in the DNS zone file. This is an administrative step that requires no changes to an organization’s e-mail or DNS software. Even if your domain has no outbound e-mail servers, you can help protect your domain from spoofing by publishing an SPF record in the DNS that states this. Follow the steps below to create and publish an SPF record for each domain name that your organization owns.
1. Determine the IP addresses of the outbound e-mail servers for the domain.
2. Identify the e-mail servers that transmit outbound e-mail for all of the domains and subdomains in your organization, as well as the IP addresses for these servers. You will need to publish a Sender ID record for each of them. If your organization uses any third parties to send e-mail on its behalf, such as an e-mail service provider or a hoster, you will also need to know their domain names. However, you do not need to know the IP addresses of their outbound e-mail servers. (You may want to encourage them to publish Sender ID records for their own domains.)
3. Create the SPF record. You can use the Sender ID Wizard described in this document to make it easier. (See www.microsoft.com/senderid/wizard.) Note You must create a separate SPF record for each domain and subdomain that sends e-mail for you. It is possible for several domains to share the same Sender ID record.
4. After you have created the SPF records for your organization, publish them in DNS TXT records. You may need the assistance of your DNS administrator, Web hoster, or registrar.
5. Ensure that your domain can be correctly identified as the purported responsible domain (PRD) for each message you send. This means that the sender’s domain must be shown in certain headers of the e-mail message. Sender ID has been carefully designed to ensure that most legitimate e-mailers, remailers, and mailing list operators already satisfy this requirement. In a few cases, such as mail forwarding services, you may need to add additional headers to e-mail messages.