What's the origin " I ken your father"

[David Black]

Its a Scottish put down? But odd.

[Electrochem]

It means "I know your father"

[Quizmonster]

The put-down element is applied to someone giving himself airs and pretending to be something special. If an ordinary sort of person points out to him that he "knows his father", he's simply telling him - the seemingly high and mighty one - that he also came from the same sort of humble origins as the speaker did. It's rather like the other Scottish claim that "We're a' Jock Thamson's bairns."
(There's an awful lot of 'hes' there, but I trust my meaning is clear enough!)

[Quizmonster]

I should perhaps have added above that I myself have more often heard it used in the past tense, "I kent yer faither."