In swank.lisp,

この辺変えてみれば?
(defparameter *loopback-interface* "127.0.0.1")

(defun setup-server (port announce-fn style dont-close coding-system)
(declare (type function announce-fn))
(init-log-output)
(let* ((socket (create-socket *loopback-interface* port))
;;;略