A denial-of-service attack is an attack in which the attacker knees down the website by increasing useless traffic on the website.
There are so many methods and tools for Dos Attacks, here is one of the easiest Dos attack method for newbies in the hacking field in easy steps.
Step 1: Copy the link form “Clone or download” button from website: https://github.com/GinjaChris/pentmenu
Step 2: Open terminal and go to Desktop
root@kali:~# cd Desktop/
Step 3: Download pentmenu
root@kali:~# git clone https://github.com/GinjaChris/pentmenu.git
Step 4: Open pentmenu folder
root@kali:~# cd pentmenu
Step 5: Run pentmenu
Step 6:select option 2>Dos
Step 7: Select option 6>Slowloris
Step 8: Set Target URL (eg- abcd.xyz)
Step 9: Set Target Port (By default it is 80)
Step 10: Set number of connections to 10000000 or according to your need and press ‘y’ for using SSL/TLS
And attack starts , to abort attack press Ctrl+c.