Sayyiduna Anas (may Allah be pleased with him) narrates: The door of the Prophet (peace and blessings be upon him) used to be knocked upon with the fingernails.
Imam al-Bazzar recorded it. Its chain contains Dirar bin Surad, who is da'if (weak).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الأدب / 12802