The Messenger of Allah ﷺ forbade that a town-dweller sell on behalf of a desert-dweller.I asked Ibn Abbas, "What is meant by 'a town-dweller selling for a desert-dweller'?"He replied, "He must not act as a broker for him."
حدثنا العباس بن عبد العظيم العنبري حدثنا عبد الرزاق أنبأنا معمر عن ابن طاوس عن أبيه
نهى رسول الله ﷺ أن يبيع حاضر لباد قلت لابن عباس ما قوله حاضر لباد قال لا يكون سمسارا
Bukhari narrated it in the Book of Sales, Chapter "Should a townsman sell for a nomad without a fee?", Hadith 2158, and others, from the hadith of Abdul-Razzaq with this wording, and Muslim in the Book of Sales, the aforementioned chapter, Hadith 1521, from the hadith of Mamar with this wording.