When the Messenger of Allah ﷺ came to someone's door, he would not face the door directly but would stand to its right or left side and say, "Peace be upon you, peace be upon you." This was because in those days, the houses did not have curtains over their doorways.
حدثنا مؤمل بن الفضل الحراني في آخرين قالوا حدثنا بقية بن الوليد حدثنا محمد بن عبد الرحمن
كان رسول الله ﷺ إذا أتى باب قوم لم يستقبل الباب من تلقاء وجهه ولكن من ركنه الأيمن أو الأيسر ويقول السلام عليكم السلام عليكم وذلك أن الدور لم يكن عليها يومئذ ستور
[Its isnad is hasan] Ahmad narrated it, 4/189, and Bukhari in Adab al-Mufrad, no. 1078, from the hadith of Baqiyyah through this route, and he explicitly stated the chain of direct hearing, and Ismail bin Ayyash corroborated him.Muhammad bin Abdul-Rahman is al-Humayri al-Himsi.