Open the DNS zone which you want to connect with Dynamic DNS. Find the A record which you want to be updated dynamically and click on the arrows on the row for this record. You will see the Dynamic URL for update of the record.
You must configure ClouDNS as a Customized Provider in your Synology NAS device with the URL below:
Following data should be filled in the DDNS settings:
Service provider: ClouDNS (this is the name, you have configured as custom provider)
Hostname: (you can leave it empty)
Username/Email: (you can leave it empty)
Password/Key: generated_key (the key that has been generated when you click on the arrows. You will get the following URL: https://ipv4.cloudns.net/api/dynamicURL/?q=generated_key (the key is located after ?q=))
Note that __PASSWORD__ and __MYIP__ are variables and you must enter them like that, not to change them to a password and an IP address.
Connect to your Synology device through SSH and:
1) open the crontab with the following command:
2) add the following line to the end of the file:
0 * * * * wget -q --read-timeout=0.0 --waitretry=5 --tries=400 --background https://ipv4.cloudns.net/api/dynamicURL/?q=generated_key
3) save the file, usually it is opened with the text editor "nano", so you can do this by Ctrl+X, Y and Enter.
A Cronjob can be also scheduled from Control Panel of your Synology device.
Open Control Panel and select Task Scheduler. Then, click on Create and select User-defined script. Type a name for your new task, make sure the user is root and fill the following command:
wget -q --read-timeout=0.0 --waitretry=5 --tries=400 --background https://ipv4.cloudns.net/api/dynamicURL/?q=generated_key
Once you add it, click on Schedule tab and set frequency to "Every hour".