Musnad Ahmad 27:621

He said: I found in my father’s book: Muhammad ibn Bakr narrated to us, Ibn Jurayj informed us, Nafi’ informed me, from Abdullah ibn Umar, who said: A man stood up in the mosque of Medina and said: "O Messenger of Allah, from where do you command us to enter into Ihram?" He said: "The Ihram station for the people of Medina is Dhu al-Hulayfah, the Ihram station for the people of Syria is al-Juhfah, and the Ihram station for the people of Najd is Qarn." Nafi’ said to me: And Ibn Umar said to me: "And they claim that the Prophet, peace and blessings of Allah be upon him, said: 'And the Ihram station for the people of Yemen is Yalamlam.'" And he used to say: "I do not remember that."