Enable Namecheap DDNS on Synology DSM

I’ve deployed several private cloud services on my Synology DS220+.
To make them accessible from outside my home network, I registered a personal domain.
Since my home network uses a dynamic IP, I need to use DDNS (Dynamic DNS) to keep the domain correctly mapped to my changing IP address.

Previously, my domain was registered with name.com, and I used dnspod.cn for DDNS — convenient because DSM has built-in support for DNSPod.

When I later registered sirenlingyu.com on namecheap.com, I discovered that Namecheap provides its own DDNS service.
So I transferred my domain from name.com to Namecheap to use their built-in DDNS directly — no need for a third-party provider anymore.

However, Synology DSM doesn’t natively support Namecheap DDNS, so we’ll need to configure it manually.
Here’s how 👇

Step 1: Add a DDNS Record on Namecheap

Type: A + Dynamic DNS Record
Host: @
Value: 127.0.0.1

Then scroll to the bottom of the page and toggle on Dynamic DNS.
You’ll get a Dynamic DNS Password — keep it safe, as we’ll need it later.

Step 2: Add a Custom DDNS Provider in Synology DSM

In your Synology DSM, go to:

Control Panel → External Access → DDNS → Customize

Add a new provider:

Service Provider: namecheap
Query URL: https://dynamicdns.park-your-domain.com/update?host=@&domain=__USERNAME__&password=__PASSWORD__&ip=__MYIP__

Save it, then add a new DDNS record:

Service Provider: Select the custom provider you just created (namecheap)
Hostname: Your domain name (e.g. sirenlingyu.com)
Username/Email: Your domain name again
Password/Key: The Dynamic DNS Password you got from Namecheap

Once done, Namecheap will automatically update your DNS record with your current IP address, keeping your domain correctly pointed even if your home IP changes.

💡 Note:
The DSM interface might show a “Failed” status during DDNS updates — you can safely ignore that.
As long as your Namecheap DNS record reflects the correct IP address, your DDNS setup is working fine.