Sayyiduna Tamim al-Dari (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "On every route into Taybah (Madinah) there stands an angel with his sword drawn; the Dajjal will never be able to enter it." And Abu Kurayb said (in the chain): Uthman bin Zayd.
Hadith Referenceالمعجم الكبير للطبراني / باب التاء / 1256