Ibrahim al-Nakha'i (may Allah have mercy on him) says that the punishment of the sodomite is that of adultery: if he is married, stoning; otherwise, he is to be lashed.
The Shaykh (may Allah have mercy on him) says that, according to what al-Rabi' bin Sulayman (may Allah have mercy on him) thought, Imam al-Shafi'i (may Allah have mercy on him) had also reverted to this view.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحدود / 17032