diff --git a/lib/puma/binder.rb b/lib/puma/binder.rb
index be1f6150..2892237f 100644
--- a/lib/puma/binder.rb
+++ b/lib/puma/binder.rb
@@ -246,7 +246,7 @@ module Puma
 
     def localhost_addresses
       addrs = TCPSocket.gethostbyname "localhost"
-      addrs[3..-1]
+      addrs[3..-1].uniq
     end
 
     # Tell the server to listen on host +host+, port +port+.