diff --git a/src/http/modules/ngx_http_geo_module.c b/src/http/modules/ngx_http_geo_module.c
index 0ec8d093b..a184a7ae3 100644
--- a/src/http/modules/ngx_http_geo_module.c
+++ b/src/http/modules/ngx_http_geo_module.c
@@ -589,7 +589,7 @@ ngx_http_geo_add_range(ngx_conf_t *cf, ngx_http_geo_conf_ctx_t *ctx,
     ngx_array_t           *a;
     ngx_http_geo_range_t  *range;
 
-    for (n = start; n <= end; n += 0x10000) {
+    for (n = start; n <= end; n = (n + 0x10000) & 0xffff0000) {
 
         h = n >> 16;