$\rightarrow$ Both ionic and metallic crystals have electrostatic forces of attraction.
$\rightarrow$ In ionic crystals these are between oppositely charged ions.In metals these are among the valence electrons and the kernels.
$\rightarrow$ Both have high melting point.
$\rightarrow$ Ionic bond is strong due to electrostatic forces of attraction whereas metallic bond may be weak or strong depending upon the number of valence electrons and the size of kernels
$\rightarrow$ In ionic bond,ions are not free to move.Hence,they cannot conduct electricity in solid state.They can do so only in molten state or in aqueous solution.