@@ -8,18 +8,29 @@ "go.alanpearce.eu/x/listenfd"
 )
 
 func (s *Server) serveTCP() error {
+	addr := joinHostPort(s.options.ListenAddress, s.options.Port)
 	s.log.Debug(
 		"fallback listener",
 		"addr",
-		net.JoinHostPort(s.options.ListenAddress, strconv.Itoa(s.options.Port)),
+		addr,
 	)
-	l, err := listenfd.GetListener(0,
-		net.JoinHostPort(s.options.ListenAddress, strconv.Itoa(s.options.Port)),
-		s.log.Named("tcp.listenfd"),
-	)
+	l, err := listenfd.GetListener(0, addr, s.log.Named("tcp.listenfd"))
 	if err != nil {
 		return err
 	}
 
 	return s.server.Serve(l)
 }
+
+func joinHostPort(host string, port int) string {
+	if len(host) < 1 {
+		return ""
+	}
+
+	portString := strconv.Itoa(port)
+	if host[0] == '[' && host[len(host)-1] == ']' {
+		return host + ":" + portString
+	}
+
+	return net.JoinHostPort(host, portString)
+}