Setting up Dynamic DNS on MyDNS.jp Using a Domain Acquired via Onamae.com

2026-08-29

This time, I took on the challenge of configuring a custom domain obtained through Onamae.com to be used as a Dynamic DNS (DDNS).

While Onamae.com does provide a Dynamic DNS service, I used MyDNS.jp instead of Onamae.com’s built-in Dynamic DNS because I wanted to use a tool called ddclient.
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I’ll introduce the step-by-step procedure in detail!

For details on the machine used, please check the following article.
Getting an Ubuntu Machine Using OCI (Oracle Cloud Infrastructure) Always Free

Acquiring a Domain on Onamae.com

First, I acquired a custom domain on Onamae.com.

• As an example, I purchased the domain “example.com".

Although Onamae.com offers a Dynamic DNS service, ddclient does not support it.
Therefore, I chose MyDNS.jp as the update destination for Dynamic DNS.

Configuring Dynamic DNS Using ddclient

I used a tool called ddclient to update the Dynamic DNS. I set up the environment with the following steps.

1. Install ddclient

• The environment used is Ubuntu 22.04. ddclient can be installed from the standard repository.

  sudo apt update
  sudo apt install ddclient

2. Introduce the unofficial ddclient

• The standard version of ddclient does not support the MyDNS.jp update protocol. By using an unofficial version created by a volunteer, integration with MyDNS.jp becomes possible.
  Get it from here. Much appreciated!~
• Overwrite the official version of ddclient with the unofficial version:

  sudo cp {非公式版ddclientのパス} /usr/sbin/ddclient

3. Fix the location of ddclient.conf

• Introducing the unofficial version changes the path of the configuration file, so I fixed it with the following steps:

  sudo mkdir /etc/ddclient
  sudo ln -s /etc/ddclient.conf /etc/ddclient/

4. Configure MyDNS.jp Nameserver Settings

• I changed the DNS settings for the domain acquired on Onamae.com to MyDNS.jp. This enables IP updates through MyDNS.jp.

5. Configure ddclient.conf

• Added the following content to /etc/ddclient.conf:

  ssl=no
  protocol=mydns
  server=ipv4.mydns.jp
  use=web, web=checkip.dyndns.org/ web-skip='IP Address'
  login={mydnsのログインID}
  password={mydnsのログインパスワード}
  {お名前.comで取得したドメイン}

Operation Check and Adjustment

1. Check and Delete Cache

• IP address caches are saved in /var/cache/ddclient/ddclient.cache. Deleting this file during testing makes it easier to check the update status:

  sudo rm /var/cache/ddclient/ddclient.cache

2. Verify IP Update

• By default, ddclient checks and updates the IP address every 300 seconds.
• Access mydns.jp to check if the IP has been updated. If it looks like the following, you’re good to go:
  DNS UPDATE : {お名前.comで取得したドメイン名}
  IPv4 UPDATE : {mydnsのログインID} {IPアドレス} (？), http, la01
• Locally, the updated content is reflected in ddclient.cache, so you can check it with the following command:

  cat /var/cache/ddclient/ddclient.cache

3. Run ddclient as a Daemon

• Once the update is successful, run ddclient as a resident background process:

  sudo systemctl enable ddclient
  sudo systemctl start ddclient

Conclusion

I built a Dynamic DNS setup using a domain acquired from Onamae.com, combined with MyDNS.jp and ddclient!

• Key Points:
  1. Although Onamae.com supports Dynamic DNS, it is incompatible with ddclient, hence the use of MyDNS.jp.
  2. Using an unofficial ddclient makes MyDNS.jp updates possible.
  3. Minor tasks such as fixing configuration file paths and deleting caches are required.

As a result, I was able to automate IP address updates and build a comfortable environment. If you are considering running Dynamic DNS for a similar purpose, please give it a try.

Also, please let me know in the comments if you have any questions or feedback!