addr

Returns the local address as an array which contains address_family, port, hostname and numeric_address.

If reverse_lookup is true or :hostname, hostname is obtained from numeric_address using reverse lookup. Or if it is false, or :numeric, hostname is same as numeric_address. Or if it is nil or omitted, obeys to ipsocket.do_not_reverse_lookup. See Socket.getaddrinfo also.

TCPSocket.open("www.ruby-lang.org", 80) {|sock|
  p sock.addr #=> ["AF_INET", 49429, "hal", "192.168.0.128"]
  p sock.addr(true)  #=> ["AF_INET", 49429, "hal", "192.168.0.128"]
  p sock.addr(false) #=> ["AF_INET", 49429, "192.168.0.128", "192.168.0.128"]
  p sock.addr(:hostname)  #=> ["AF_INET", 49429, "hal", "192.168.0.128"]
  p sock.addr(:numeric)   #=> ["AF_INET", 49429, "192.168.0.128", "192.168.0.128"]
}