I have just done a fresh install of 12.04.2 and found out that i could not ssh to this PC. I tried to install openssh-server but it said that "Package openssh-server is not available..." What is missing?
Go to the Ubuntu Software Centre and browse to the Edit -> Software Sources -> Ubuntu Software tab. Then select Other -> Select Best Server under Download From.
Afterwards run in a terminal (Ctrl+Alt+T):
sudo apt-get update && sudo apt-get install openssh-server
Follow the on-screen instructions. This will resolve the issue.
I was following the advice to remove and re-install openssh-server via CLI, but got an error saying the package was not available.
apt-get then tried again with success.
So, the sequence that succeeded was:
sudo apt-get remove openssh-client openssh-server sudo apt-get update sudo apt-get install openssh-server
I had the same problem because in installed Ubuntu on a virtual machine, but i didn't connect it to internet because i used a private switch. I just changed the switch and connect it to internet with a private switch. After that i changed the sources code and chose one for my case (Germany). Now it working. You can try the same and i hope everything gonna for you too. (Don't forget to run the update)