How are ionic bonds and van der Waals forces similar and different?

They are both attractions between positive and negative. They are different in that ionic bonds are bonds between ions, van der Waals forces are attractions between molecules

occurs when a metal loses its outer electrons to become positively charged and non-metals gain electrons to become negatively charged. In doing so both the metal and non-metal achieve stable outer electron arrangements, the same as the nearest noble gas. The now oppositely charged ions attract each other in a large 3D lattice arrangement. Ionic bonds are very strong and thus tend to have very high melting and boiling points as it takes a great deal of energy to overcome the attractions between the ions.

Van der Waals forces (London dispersion forces, permanent dipole - permanent dipole and hydrogen bonding) occur between covalent molecules and monatomic gases. These attractions occur due to the movement of electrons within molecules creating dipoles (temporary or permanent) these dipoles are then weakly attracted to the oppositely charged dipole on a neighbouring molecule. Due to these attractions being weak, the substances tend to be gases, liquids or low melting point solids as it does not take a large amount of energy to overcome the weak attractions between molecules.