diff --git a/src/http/ngx_http_upstream.c b/src/http/ngx_http_upstream.c
index b02caa67d..404be48ef 100644
--- a/src/http/ngx_http_upstream.c
+++ b/src/http/ngx_http_upstream.c
@@ -161,6 +161,12 @@ ngx_http_upstream_header_t  ngx_http_upstream_headers_in[] = {
                  offsetof(ngx_http_upstream_headers_in_t, last_modified),
                  ngx_http_upstream_copy_last_modified, 0, 0 },
 
+    { ngx_string("ETag"),
+                 ngx_http_upstream_process_header_line,
+                 offsetof(ngx_http_upstream_headers_in_t, etag),
+                 ngx_http_upstream_copy_header_line,
+                 offsetof(ngx_http_headers_out_t, etag), 0 },
+
     { ngx_string("Server"),
                  ngx_http_upstream_process_header_line,
                  offsetof(ngx_http_upstream_headers_in_t, server),