That is because there is not a package in the standard repositories with such a name, to get the latest in the repositories then run:
sudo apt-get install virtualbox
If you already have the virtualbox
.deb
file you wish to install it then simply cd
into the relevant folder and run (<package-name>
being the name of the .deb
file you wish to install):
sudo dpkg -i <package-name>
If you do not already have it then you may download it from the official page (there are download links at the top of the page).
If you want it from the official VirtualBox repository though you will need to run:
echo "deb http://download.virtualbox.org/virtualbox/debian $(lsb_release -cs) contrib" | sudo tee /etc/apt/sources.list.d/oracle-virtualbox.list
Then add the key (for version 16.04 and above):
wget -q https://www.virtualbox.org/download/oracle_vbox_2016.asc -O- | sudo apt-key add -
Or this one (for version below 16.04):
wget -q https://www.virtualbox.org/download/oracle_vbox.asc -O- | sudo apt-key add -
And then run:
sudo apt-get update
sudo apt-get install dkms
sudo apt-get install virtualbox-5.1
Which is currently (at the time of this writing) the latest version, though you may replace the version number with whichever you like the install that version.
Source and further reference.
To answer your second question: the guest addition comes with the VirtualBox version you install. You can install it on a VM by going Devices > Insert Guest Additions Installation CD
(though you will have to do this again every time you upgrade your VirtualBox version as the guest additions installation doesn't upgrade by itself on your VMs). Ubuntu will ask you if you wish to run the contents of the inserted CD, say you do and then it will install it.