Set Up Email Domain Authentication
To help ensure your email reaches your recipients' inboxes, you can set up custom DomainKeys Identified Mail (DKIM) authentication for your domain. Most service providers like Google, Yahoo, and Microsoft use DKIM as a way to scan incoming emails for spam or spoofed addresses. Emails that fail authentication are more likely to arrive in a spam or junk folder.
To use DKIM with Bing you can either add CNAME records to your DNS or insert a public/private key into your DNS.
To set up DKIM by adding CNAME records to your domain follow the below steps.
In your domain’s DNS records create 3 CNAME records as per our example below for example.com.au.
bingmail1._domainkey.example.com.au. 3600 IN CNAME dkim1.ci.com.au. bingmail2._domainkey.example.com.au. 3600 IN CNAME dkim2.ci.com.au. bingmail3._domainkey.example.com.au. 3600 IN CNAME dkim3.ci.com.au.
Once your DNS data is ready, notify Bing Customer Service so that Bing can enable DKIM signing for your Bing-originated email.
See RFC standards for more information on DKIM. There are many other resources on the internet that will further explain DKIM.
Private/Public Key Method
To set up the private/public key method please contact Bing Customer Service.
Bing also recommends that you add Bing's mail servers to any existing or new Sender Policy Framework (SPF) TXT record. A typical SPF for a company (example.com.au) using O365 will look like this.
example.com.au. 3600 IN TXT "v=spf1 include:spf.protection.outlook.com -all"
Adding Bing's mail servers to your existing SPF DNS data look like this:
example.com.au. 3600 IN TXT "v=spf1 include:spf.protection.outlook.com include:spf.bingmail.com.au mx -all"
Full SPF configuration for your domain may vary, but the example shows how it might be configured.
See RFC standards for more information on setting up SPF.