Brahmins are one of the members of the four Varnas described by Krishna Bhagavan in Bhagavad Gita. The divisions in to four categories as Brahmins, Kshtriyas, Vaisyas and Sudras was based on the allocation of complimentary duties of the four Varnas. Brahmins were assigned the study of Vedas and protection of them. Vaisyas took care of Commerce, Kshatriyas ruling of the land and Sudras for other duties not covered bty the members of the first three Varnas. No one is superior to the other among the four Varnas in the eyes of the Lord. All are his children.
Vaishnavas are Vishnu dasas, who devote their entire life to the service of Bhagavan or Bhagavatas . The Vishnu Dasas , who happen to be Brahmins by Birth are identifiable as Iyengars. Brahmins can be Iyengars, Iyers and Raos. Veda Adhyayanam and performance of Yagas and Yagnas and intrepretation of Sacred scriptures were their assigned duties. The late Paramacharya of Kanchi has made a distinction between Brahmanas and Brahmana Bandhus. He has described the latter as the one born of Brahman parents, but not observant of the duties assigned by the Sastras and Vedas to Brahmins.
See also: Vaishnava Iyengar