The Messenger of Allah ﷺ forbade shighar marriage. Shighar is when a man gives his daughter in marriage on the condition that the other man gives him his daughter in marriage, with no dowry between them.
أن رسول الله ﷺ نهى عن الشغار. والشغار أن يزوج الرجل ابنته على أن يزوجه الآخر ابنته. ليس بينهما صداق.
Malik narrated it in the Book of Marriage (24), from Nafi, from Abdullah bin Umar, and he mentioned it. Bukhari narrated it in the Book of Marriage (5112), and Muslim in the Book of Marriage (57:1415), both of them through the route of Malik, in the same manner. Bukhari also narrated it in the Book of Legal Tricks (6960), and Muslim in the Book of Marriage (58), through the route of Ubaydullah bin Umar, from Nafi, in the same manner. In it, it says, I said to Nafi, "What is shighar?" He said, "It is when a man marries off his daughter and another man marries off his daughter to him, without a dowry, or when a man marries off his sister and another man marries off his sister to him, without a dowry."This makes clear that the explanation of shighar in Malik's route is part of Nafi's own statement, and Abdull-Haq Ishbili affirmed this decisively in Al-Jam bayn Sahihayn (2/388).