To create an MX Record at DynDNS.com
1. Sign in to your account at www.DynDNS.com.
2. In the My Services section, click My Zones/Domains.
The Zone Level Services page opens.
3. In the Service column next to your domain name, click Custom DNS Service.
The DNS setting page for the domain opens.
4. Click Edit MX List.
The Mail Exchanger setting page for the domain opens.
5. In the Mail Exchangers box, in the first line, type or paste the MX record information provided by Microsoft Online Services (similar to Mail.Global.FrontBridge.com).
Note: To make this your highest priority MX record, ensure the information is entered in the first line.
6. Click Save Mail Exchangers.
With Exchange Online, in order to allow your domain to receive e-mail, you need to modify the Mail Exchange