It's a play off of the war dialing phrase where you would have your computer dial every phone number within a prefix. 212-555-0001, -0002,... -9999. You would log every number that was answered by another computer for later investigation.
Classic movie scene based on the concept from War Games:
Classic movie scene based on the concept from War Games:
https://www.youtube.com/watch?v=zb1r_uKOew4