Shabab al-Usfuri said: Sayyiduna Anasah (may Allah be pleased with him), the freedman of the Messenger of Allah (peace and blessings be upon him), used to perform the service of seeking permission for those who came to visit him (peace and blessings be upon him).
Hadith Referenceالمعجم الكبير للطبراني / باب الألف / 775