Wife's Surname and Child's Surname - Whats the Islamic way?

Re: Wife's Surname and Child's Surname - Whats the Islamic way?

^“Call them by (the names of) their fathers: that is juster in the sight of Allah. But if ye know not their father's (names, call them) your Brothers in Faith…” (Al-Ahzab: 5)

The Prophet (peace and blessings be upon him) said, "Whosoever will claim the name of anyone other than his father will not even get the smell of Paradise." (Reported by Ibn Majah)"