Halakha Ayub 28:9: Shulchan Arukh, Yoreh De'ah

He should not greet his rabbi with peace, nor return a greeting of peace to him in the manner of other people. Rather, he should bow before him and say to him in awe and reverence, "Peace be upon you, my rabbi." And if his rabbi greeted him with peace, he says to him, "Peace be upon you, my teacher and my rabbi." (And this is the custom. And some say that a student should not greet his rabbi at all, as it is stated, "The youths saw me and hid.") (Yerushalmi, cited by Hagahot Maimoni chapter 5, and so wrote Toldot Adam v'Chavah netiv 2, and Beit Yosef in the name of Rabbeinu Yonah). And he should not remove his tefillin in the presence of his rabbi, and he should not recline in his presence; rather, he should sit as one sits before a king. (If his rabbi was sitting at a meal with others, he takes permission from his rabbi and afterwards from the others) (Rokeach siman 335). And he should not pray in front of him, nor behind him, nor at his side. And needless to say, it is forbidden to walk at his side; rather, he should distance himself behind his rabbi, and he should not be aligned directly behind him, but should position himself to the side, whether when praying with him or walking with him. And outside of four cubits, everything is permitted. (And see Orach Chayim siman 94). And he should not enter a bathhouse with him unless he needs him. Gloss: And if the student was in the bathhouse prior to his rabbi, and his rabbi arrived there, he does not need to leave (Mahariu on laws). And all of this applies only in a place where they walk completely naked in the bathhouse, but in a place where they wear pants, it is permitted (Agudah chapter Makom SheNahagu). And thus is the simple custom, to enter a bathhouse with his rabbi, his father, his father-in-law, his mother's husband, and his sister's husband, even though in the Gemara they forbade all of them; and it is all for the reason that now they wear pants. And he should not sit in his presence until he tells him to sit. And he should not stand until he tells him to stand, or until he receives permission to stand. And when he takes his leave from his presence, he should not turn his back to him, but should step backward with his face toward his rabbi's face. Gloss: And one who takes leave of his rabbi and received permission from him, and lodged in the city, must go back and receive permission from him (Talmud, first chapter of Moed Katan and Rabbeinu Yerocham). And this is specifically if he did not tell him initially that he wanted to lodge in the city, but if he told him at the time he received permission, he does not need to go back and receive permission from him (Ran there). And he should not sit in his place, and he should not decide his words in his presence, and he should not contradict his words. And he is obligated to stand before him from when he sees him from afar, as far as his eyes can see, until he is hidden from him so he cannot see his stature, and afterwards he may sit. And even if he was riding, he must stand before him, because it is considered like walking. Gloss: Some say that a person is not obligated to stand before his rabbi except morning and evening (Tur in the name of the Rambam), and specifically in the rabbi's house. But in the presence of others who do not know that he stood before him, he is obligated to stand (Beit Yosef in the name of the Tosafot, and Mordechai in the name of the R.I. and Af Al Pi).