Humayd says: I saw Sayyiduna Anas bin Malik (may Allah be pleased with him) performing ablution. He wiped the outer and inner parts of his ears, and we looked at him, so he said: Ibn Umm Abd (Abdullah bin Mas'ud, may Allah be pleased with him) used to command us to do exactly this.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 304