I want to edit the dyndns.ini file, but I do not its location.

The location of the dyndns.ini file used by the program is saved inside registry. To know where it is, do the following steps.

1. Press Windows+R keys (pressing R key while pressing the Windows key). You will see the Run command box.
2. Type regedit on the box, and click the OK button. The Registry Editor will be displayed.
3. Inside the Registry Editor, navigate to the HKEY_CURRENT_USER\Software\Kana Solution\Kana Dynamic IP Updater key. On the right side, you will see the IniFile entry, which specify the location of the dyndns.ini file used.

If you are running Kana Dynamic IP Updater as service, this key may not under your profile branch, but under the user who run the service.