diff --git a/servers/slapd/bconfig.c b/servers/slapd/bconfig.c
index 3d3771b838..a5cf6730cf 100644
--- a/servers/slapd/bconfig.c
+++ b/servers/slapd/bconfig.c
@@ -2171,7 +2171,7 @@ slap_loglevel_get( struct berval *s, int *l )
 	rc = slap_verbmasks_append( &loglevel_ops, i, s, loglevel_ignore );
 
 	if ( rc != 0 ) {
-		Debug( LDAP_DEBUG_ANY, "slap_loglevel_register(%lu, \"%s\") failed\n",
+		Debug( LDAP_DEBUG_ANY, "slap_loglevel_get(%lu, \"%s\") failed\n",
 			i, s->bv_val, 0 );
 
 	} else {
diff --git a/servers/slapd/main.c b/servers/slapd/main.c
index 38348533d4..46d24ba1db 100644
--- a/servers/slapd/main.c
+++ b/servers/slapd/main.c
@@ -222,13 +222,31 @@ parse_syslog_level( const char *arg, int *levelp )
 }
 
 int
-parse_debug_level( const char *arg, int *levelp )
+parse_debug_unknowns( char **unknowns, int *levelp )
+{
+	int i, level, rc = 0;
+
+	for ( i = 0; unknowns[ i ] != NULL; i++ ) {
+		level = 0;
+		if ( str2loglevel( unknowns[ i ], &level )) {
+			fprintf( stderr,
+				"unrecognized log level \"%s\"\n", unknowns[ i ] );
+			rc = 1;
+		} else {
+			*levelp |= level;
+		}
+	}
+	return rc;
+}
+
+int
+parse_debug_level( const char *arg, int *levelp, char ***unknowns )
 {
 	int	level;
 
 	if ( arg != NULL && arg[ 0 ] != '-' && !isdigit( arg[ 0 ] ) )
 	{
-		int	i, goterr = 0;
+		int	i;
 		char	**levels;
 
 		levels = ldap_str2charray( arg, "," );
@@ -237,12 +255,11 @@ parse_debug_level( const char *arg, int *levelp )
 			level = 0;
 
 			if ( str2loglevel( levels[ i ], &level ) ) {
+				/* remember this for later */
+				ldap_charray_add( unknowns, levels[ i ] );
 				fprintf( stderr,
-					"unrecognized log level "
-					"\"%s\"\n", levels[ i ] );
-				goterr = 1;
-				/* but keep parsing... */
-
+					"unrecognized log level \"%s\" (deferred)\n",
+					levels[ i ] );
 			} else {
 				*levelp |= level;
 			}
@@ -250,10 +267,6 @@ parse_debug_level( const char *arg, int *levelp )
 
 		ldap_charray_free( levels );
 
-		if ( goterr ) {
-			return 1;
-		}
-
 	} else {
 		if ( lutil_atoix( &level, arg, 0 ) != 0 ) {
 			fprintf( stderr,
@@ -349,6 +362,9 @@ int main( int argc, char **argv )
 	struct sync_cookie *scp = NULL;
 	struct sync_cookie *scp_entry = NULL;
 
+	char **debug_unknowns = NULL;
+	char **syslog_unknowns = NULL;
+
 	char *serverNamePrefix = "";
 	size_t	l;
 
@@ -486,7 +502,7 @@ int main( int argc, char **argv )
 			int	level = 0;
 
 			no_detach = 1;
-			if ( parse_debug_level( optarg, &level ) ) {
+			if ( parse_debug_level( optarg, &level, &debug_unknowns ) ) {
 				goto destroy;
 			}
 #ifdef LDAP_DEBUG
@@ -541,7 +557,7 @@ int main( int argc, char **argv )
 		}
 
 		case 's':	/* set syslog level */
-			if ( parse_debug_level( optarg, &ldap_syslog ) ) {
+			if ( parse_debug_level( optarg, &ldap_syslog, &syslog_unknowns ) ) {
 				goto destroy;
 			}
 			break;
@@ -707,6 +723,21 @@ unhandled_option:;
 		goto destroy;
 	}
 
+	if ( debug_unknowns ) {
+		rc = parse_debug_unknowns( debug_unknowns, &slap_debug );
+		ldap_charray_free( debug_unknowns );
+		debug_unknowns = NULL;
+		if ( rc )
+			goto destroy;
+	}
+	if ( syslog_unknowns ) {
+		rc = parse_debug_unknowns( syslog_unknowns, &ldap_syslog );
+		ldap_charray_free( syslog_unknowns );
+		syslog_unknowns = NULL;
+		if ( rc )
+			goto destroy;
+	}
+
 	if ( check & CHECK_CONFIG ) {
 		fprintf( stderr, "config check succeeded\n" );
 
diff --git a/servers/slapd/proto-slap.h b/servers/slapd/proto-slap.h
index 5859ecad3e..5bdba47717 100644
--- a/servers/slapd/proto-slap.h
+++ b/servers/slapd/proto-slap.h
@@ -1004,7 +1004,9 @@ LDAP_SLAPD_F (int) lock_fclose LDAP_P(( FILE *fp, FILE *lfp ));
  * main.c
  */
 LDAP_SLAPD_F (int)
-parse_debug_level LDAP_P(( const char *arg, int *levelp ));
+parse_debug_level LDAP_P(( const char *arg, int *levelp, char ***unknowns ));
+LDAP_SLAPD_F (int)
+parse_debug_unknowns LDAP_P(( char **unknowns, int *levelp ));
 
 /*
  * matchedValues.c
diff --git a/servers/slapd/slapcommon.c b/servers/slapd/slapcommon.c
index 9f99363dc8..59e1e01cf3 100644
--- a/servers/slapd/slapcommon.c
+++ b/servers/slapd/slapcommon.c
@@ -189,6 +189,7 @@ slap_tool_init(
 	char *filterstr = NULL;
 	char *subtree = NULL;
 	char *ldiffile	= NULL;
+	char **debug_unknowns = NULL;
 	int rc, i, dbnum;
 	int mode = SLAP_TOOL_MODE;
 	int truncatemode = 0;
@@ -267,7 +268,7 @@ slap_tool_init(
 		case 'd': {	/* turn on debugging */
 			int	level = 0;
 
-			if ( parse_debug_level( optarg, &level ) ) {
+			if ( parse_debug_level( optarg, &level, &debug_unknowns ) ) {
 				usage( tool, progname );
 			}
 #ifdef LDAP_DEBUG
@@ -454,6 +455,14 @@ slap_tool_init(
 		exit( EXIT_FAILURE );
 	}
 
+	if ( debug_unknowns ) {
+		rc = parse_debug_unknowns( debug_unknowns, &slap_debug );
+		ldap_charray_free( debug_unknowns );
+		debug_unknowns = NULL;
+		if ( rc )
+			exit( EXIT_FAILURE );
+	}
+
 	at_oc_cache = 1;
 
 	switch ( tool ) {