Watch the Mark Knopfler online guitar lesson by Jeff McErlain from Kings of Tone
Mark Knopfler uses many different guitars but I mostly associate him with a Stratocaster. That's the guitar used on "Sultans of Swing", "Down To The Water Line", and other early hits. In sessions when people ask for a Mark Knopfler sound they usually mean a Strat in the out of phase 2 and 4 positions. He like all great players really utilizes the guitars tone and volume knobs to change his sound.