Vnc

Ubuntu-to-Ubuntu

tightvnc

Solid but more work.

vino & remina

Using the "Ubuntu way", everything is supposed to be brought together under [mh-ubuntu-settings] Ubuntu Settings > Sharing. (but it's crap, read on...)

The packages it needs underneath are:

sudo apt-get install vino # VNC server; RESTART GNOME after installation
sudo apt-get install remina # VNC client

Ubuntu screwed the pooch on vino-server config, wtf you idiots. It's just some fucking app with no systemd support. Well fuck if I'm jumping hoops when the next LTS release is weeks away. Fuck you ubuntu. Just run the god damned thing directly

# allow local connections
gsettings set org.gnome.Vino network-interface lo

# see all settings
gsettings list-keys org.gnome.Vino

# run the fucker
/usr/lib/vino/vino-server &

Consider other VNC servers instead that allow startup on boot?