diff -up ./src/yppasswd.c.shadow ./src/yppasswd.c --- ./src/yppasswd.c.shadow 2010-04-21 11:24:15.000000000 +0200 +++ ./src/yppasswd.c 2013-05-06 22:31:39.984229577 +0200 @@ -449,6 +449,7 @@ verifypassword (struct passwd *pwd, char passwdlen = get_passwd_len (pwd->pw_passwd); if (pwd->pw_passwd[0] + && 0 != strcmp (pwd->pw_passwd, "x") /* don't check shadow passwords */ && !strncmp (pwd->pw_passwd, crypt (pwdstr, pwd->pw_passwd), passwdlen) && uid) {