Below is a step by step guide on how to enable dynamic DNS in your Synology device.
In your Synology device click “Control Panel”.
Locate and click “DDNS” under “Network Services”.
Select No-IP from the drop-down menu showcasing the Service Providers and input your No-IP account information.
Service Provider: NoIP.com
Hostname: Input the hostname that you created with No-IP
Username: Input the email address or username attached to your No-IP account
Password: Input your No-IP account password.
External address: Leave this alone
Heartbeat: Leave this alone