--- a/src/http/ngx_http_core_module.c
+++ b/src/http/ngx_http_core_module.c
@@ -3094,17 +3094,24 @@ ngx_http_core_server_name(ngx_conf_t *cf
 
     ch = value[1].data[0];
 
-    if (cscf->server_name.data == NULL && value[1].len) {
-        name = value[1];
-
-        if (ch == '.') {
-            name.len--;
-            name.data++;
-        }
-
-        cscf->server_name.len = name.len;
-        cscf->server_name.data = ngx_pstrdup(cf->pool, &name);
-        if (cscf->server_name.data == NULL) {
+    if (cscf->server_name.data == NULL) {
+        if (value[1].len) {
+            name = value[1];
+
+            if (ch == '.') {
+                name.len--;
+                name.data++;
+            }
+
+            cscf->server_name.len = name.len;
+            cscf->server_name.data = ngx_pstrdup(cf->pool, &name);
+            if (cscf->server_name.data == NULL) {
+                return NGX_CONF_ERROR;
+            }
+
+        } else {
+            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
+                               "the first server name must not be empty");
             return NGX_CONF_ERROR;
         }
     }
@@ -3113,8 +3120,7 @@ ngx_http_core_server_name(ngx_conf_t *cf
 
         ch = value[i].data[0];
 
-        if (value[i].len == 0
-            || (ch == '*' && (value[i].len < 3 || value[i].data[1] != '.'))
+        if ((ch == '*' && (value[i].len < 3 || value[i].data[1] != '.'))
             || (ch == '.' && value[i].len < 2))
         {
             ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,