A'yan al-Jaramizi said: I came to Sayyiduna Anas bin Malik (may Allah be pleased with him) while he was in his entrance hall. I greeted him with salam and asked: May I come in? He said: "This is a place for which permission is not sought."
Hadith Referenceالمعجم الكبير للطبراني / باب الألف / 693