diff -uNr ruby-ldap-0.8.3.orig/conn.c ruby-ldap-0.8.3/conn.c
--- ruby-ldap-0.8.3.orig/conn.c	2004-11-18 17:06:45.382124120 -0800
+++ ruby-ldap-0.8.3/conn.c	2004-11-18 17:08:23.544201216 -0800
@@ -278,6 +278,16 @@
 };
 
 VALUE
+rb_ldap_conn_bound(VALUE self)
+{
+  RB_LDAP_DATA *ldapdata;
+
+  GET_LDAP_DATA(self,ldapdata);
+
+  return ldapdata->bind == 0 ? Qfalse : Qtrue;
+};
+
+VALUE
 rb_ldap_conn_set_option(VALUE self, VALUE opt, VALUE data)
 {
   /* ldap_set_option() is defined in IETF draft */
@@ -305,6 +315,8 @@
   case LDAP_OPT_TIMELIMIT:
   case LDAP_OPT_RESTART:
   case LDAP_OPT_PROTOCOL_VERSION:
+     if( ldapdata->bind != 0)
+       rb_raise(rb_eLDAP_ResultError, "can't set LDAP protocol version after bind");
   case LDAP_OPT_ERROR_NUMBER:
 #ifdef LDAP_OPT_SSL
   case LDAP_OPT_SSL:
@@ -1276,6 +1288,7 @@
   rb_ldap_conn_define_method("start_tls", rb_ldap_conn_start_tls_s, -1);
   rb_ldap_conn_define_method("simple_bind", rb_ldap_conn_simple_bind_s, -1);
   rb_ldap_conn_define_method("bind", rb_ldap_conn_bind_s, -1);
+  rb_ldap_conn_define_method("bound?", rb_ldap_conn_bound, 0);
   rb_ldap_conn_define_method("unbind", rb_ldap_conn_unbind, 0);
   rb_ldap_conn_define_method("set_option", rb_ldap_conn_set_option, 2);
   rb_ldap_conn_define_method("get_option", rb_ldap_conn_get_option, 1);