1. Edit httpd-xampp.conf file
nano /opt/lampp/etc/extra/httpd-xampp.conf2. Edit previous line to following to restrict IP access to LAN only.
<Directory "/opt/lampp/phpmyadmin">
AllowOverride AuthConfig
Order Deny,Allow
Deny from all
Require all granted
Allow from 192.168.0.0/24
</Directory>
3. Restart service
service xampp restart