You need to be sure if the location of deb it is in accordance with the command. After installing, start Splunk server by following this command:
sudo dpkg -i Downloads/splunk-6.6.3-e21ee54bc796-linux-2.6-amd64.deb
You successfully installed Splunk Server. The Splunk web interface is at http://youdomain:8000 or http://youripaddress:8000 Enjoy Splunk! If you have questions you can always ping us on chat or open a support ticket for help. Try us free for one full month today!
sudo /opt/splunk/bin/splunk start