getpeername

        # BasicSocket.getpeername

(from ruby core)
---
    basicsocket.getpeername => sockaddr

---

Returns the remote address of the socket as a sockaddr string.

    TCPServer.open("127.0.0.1", 1440) {|serv|
      c = TCPSocket.new("127.0.0.1", 1440)
      s = serv.accept
      p s.getpeername #=> "\x02\x00\x82u\x7F\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00"
    }

If Addrinfo object is preferred over the binary string, use
BasicSocket#remote_address.