--- a/src/http/modules/ngx_http_proxy_module.c
+++ b/src/http/modules/ngx_http_proxy_module.c
@@ -402,6 +402,7 @@ static ngx_keyval_t  ngx_http_proxy_head
     { ngx_string("Host"), ngx_string("$proxy_host") },
     { ngx_string("Connection"), ngx_string("close") },
     { ngx_string("Keep-Alive"), ngx_string("") },
+    { ngx_string("Expect"), ngx_string("") },
     { ngx_null_string, ngx_null_string }
 };
 

--- a/src/http/ngx_http_core_module.c
+++ b/src/http/ngx_http_core_module.c
@@ -25,6 +25,7 @@ typedef struct {
 static ngx_int_t ngx_http_core_find_location(ngx_http_request_t *r);
 static ngx_int_t ngx_http_core_find_static_location(ngx_http_request_t *r,
     ngx_http_location_tree_node_t *node);
+static ngx_int_t ngx_http_core_send_continue(ngx_http_request_t *r);
 
 static ngx_int_t ngx_http_core_preconfiguration(ngx_conf_t *cf);
 static void *ngx_http_core_create_main_conf(ngx_conf_t *cf);
@@ -771,7 +772,7 @@ ngx_http_core_find_config_phase(ngx_http
 {
     u_char                    *p;
     size_t                     len;
-    ngx_int_t                  rc;
+    ngx_int_t                  rc, expect;
     ngx_http_core_loc_conf_t  *clcf;
 
     r->content_handler = NULL;
@@ -815,6 +816,15 @@ ngx_http_core_find_config_phase(ngx_http
         return NGX_OK;
     }
 
+    if (r->headers_in.expect) {
+        expect = ngx_http_core_send_continue(r);
+
+        if (expect != NGX_OK) {
+            ngx_http_finalize_request(r, expect);
+            return NGX_OK;
+        }
+    }
+
     if (rc == NGX_DONE) {
         r->headers_out.location = ngx_list_push(&r->headers_out.headers);
         if (r->headers_out.location == NULL) {
@@ -1244,6 +1254,45 @@ ngx_http_core_find_static_location(ngx_h
 }
 
 
+static ngx_int_t
+ngx_http_core_send_continue(ngx_http_request_t *r)
+{
+    ngx_int_t   n;
+    ngx_str_t  *expect;
+
+    if (r->expect_tested) {
+        return NGX_OK;
+    }
+
+    r->expect_tested = 1;
+
+    expect = &r->headers_in.expect->value;
+
+    if (expect->len != sizeof("100-continue") - 1
+        || ngx_strncasecmp(expect->data, (u_char *) "100-continue",
+                           sizeof("100-continue") - 1)
+           != 0)
+    {
+        return NGX_OK;
+    }
+
+    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "send 100 Continue");
+
+    n = r->connection->send(r->connection,
+                            (u_char *) "HTTP/1.1 100 Continue" CRLF CRLF,
+                            sizeof("HTTP/1.1 100 Continue" CRLF CRLF) - 1);
+
+    if (n == sizeof("HTTP/1.1 100 Continue" CRLF CRLF) - 1) {
+        return NGX_OK;
+    }
+
+    /* we assume that such small packet should be send successfully */
+
+    return NGX_HTTP_INTERNAL_SERVER_ERROR;
+}
+
+
 ngx_int_t
 ngx_http_set_content_type(ngx_http_request_t *r)
 {

--- a/src/http/ngx_http_request.c
+++ b/src/http/ngx_http_request.c
@@ -106,6 +106,10 @@ ngx_http_header_t  ngx_http_headers_in[]
                  offsetof(ngx_http_headers_in_t, transfer_encoding),
                  ngx_http_process_header_line },
 
+    { ngx_string("Expect"),
+                 offsetof(ngx_http_headers_in_t, expect),
+                 ngx_http_process_unique_header_line },
+
 #if (NGX_HTTP_GZIP)
     { ngx_string("Accept-Encoding"),
                  offsetof(ngx_http_headers_in_t, accept_encoding),

--- a/src/http/ngx_http_request.h
+++ b/src/http/ngx_http_request.h
@@ -171,6 +171,7 @@ typedef struct {
     ngx_table_elt_t                  *if_range;
 
     ngx_table_elt_t                  *transfer_encoding;
+    ngx_table_elt_t                  *expect;
 
 #if (NGX_HTTP_GZIP)
     ngx_table_elt_t                  *accept_encoding;
@@ -467,6 +468,7 @@ struct ngx_http_request_s {
     unsigned                          request_complete:1;
     unsigned                          request_output:1;
     unsigned                          header_sent:1;
+    unsigned                          expect_tested:1;
     unsigned                          done:1;
     unsigned                          utf8:1;