Q. Can one comply with the mitzva of Kabbolas Pnei Horav (visiting or calling on one’s Rov during a Chag) by calling on the phone during Chol Hamoed, when it was difficult to visit personally?
A. Poskim disagree whether the mitzva of Kabbolas Pnei Horav Baregel is Biblical (Sdei Chemed – Cheis: 100, quoting Bnei Yehuda) or Rabbinical (Shaar Efraim 38 and others).
They also disagree whether it applies in our days. Shulchan Aruch omits it. Noda Beyehuda (2: O.H. 4) maintains that it does not. Orchos Rabbenu also asserts that it refers only to Rabo Mubak or prime teacher and in our times we learn mostly from seforim.
However, Yaaros Devash (1: 12), Kabo Dekushyiso (81) and others opine that it does apply.
Halichos Chaim (2: p. 100) quoting R”Ch Kanievsky Shlit’a is of the opinion that you do not comply by calling on the phone.
Horav Shlomo Miller’s Shlit’a opinion is that in principle we follow the opinion of the Noda Beyehuda (ibid.), however there are other “inyonim” and important issues involved such as Kavod Hatorah, honoring and learning it; and these can be complied with even in our days and even by calling in.
Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit’a