Is it permissible to respond to greetings and congratulations from female students—such as "Good morning," "How are you?," or "Blessed Friday"—that punctuate academic discussions on social media?

One should avoid greeting non-mahram (definition) women. Jurists have disliked initiating or returning greetings to non-mahram women, unless she is an old woman, in which case there is no harm in verbally returning her greeting. However, if she is young and there is fear of temptation, then greeting her or her returning the greeting is disliked by the Malikis, Shafi'is, and Hanbalis. The Hanafis stated that a man should return a woman's greeting to himself if she greets him, and she should return his greeting to herself if he greets her. The Shafi'is explicitly stated that it is impermissible for her to return his greeting. Many tribulations begin with greetings and salutations. The Prophet (peace be upon him) warned against the temptation of women, saying: "Beware of women, for the first tribulation of the Children of Israel was concerning women," and he said: "I have not left behind me any trial more harmful to men than women."