Customize Namecheap DDNS script for Synology

sudo -i
wget https://www.xfelix.com/wp-content/uploads/2017/06/namecheap.zip
unzip namecheap.zip
Extract and move namecheap.php to /usr/syno/bin/ddns/

Grant privilege
sudo chmod 755 /usr/syno/bin/ddns/namecheap.php

Edit DDNS Provider list
sudo vi /etc.defaults/ddns_provider.conf
Insert
[Namecheap]
modulepath=/usr/syno/bin/ddns/namecheap.php
queryurl=https://dynamicdns.park-your-domain.com/

In the DSM web interface, open the DDNS menu
Hostname: example.com
Username/Email: www
Password: nameCheap DDNS passkey