diff --git a/src/libstrongswan/settings/settings_lexer.l b/src/libstrongswan/settings/settings_lexer.l
index 176387f1f..581f8347f 100644
--- a/src/libstrongswan/settings/settings_lexer.l
+++ b/src/libstrongswan/settings/settings_lexer.l
@@ -146,8 +146,6 @@ static void include_files(parser_helper_t *ctx);
 	\\n     yyextra->string_add(yyextra, "\n");
 	\\r     yyextra->string_add(yyextra, "\r");
 	\\t     yyextra->string_add(yyextra, "\t");
-	\\b     yyextra->string_add(yyextra, "\b");
-	\\f     yyextra->string_add(yyextra, "\f");
 	\\\r?\n /* merge lines that end with EOL characters */
 	\\.     yyextra->string_add(yyextra, yytext+1);
 	[^\\\n"]+			{