I cannot enable ssh on raspberry pi 3 model b+ which is booted with ubuntu mate 18.04. I do not see ssh option in raspi-config interface tab.
The SSH server isn't preinstalled. You can install it for Ubuntu MATE using the Terminal:
sudo apt install openssh-server
It can also be installed graphically under the Servers tab in Software Boutique.
If this is the latest version of UbM18.04, then I found the ssh server was installed, but no valid keys had been generated (see ssh service status forclue) - this wasn't the aarch64 version.
Though I've already installed ssh server on Rpi I still get the error message of connection closed by my pi ip address port 22
I have run into the issue with no ssh keys present. The following command should do the trick:
sudo dpkg-reconfigure openvn-server
Isn't it openssh one needs to reconfigure?
You are quite correct. My typo. dpkg-reconfigure is the magic command which it took me some time to find. Of course openssh-server is the application which needs fixing.