diff --git a/changes/bug2279 b/changes/bug2279
new file mode 100644
index 0000000000..b796cda761
--- /dev/null
+++ b/changes/bug2279
@@ -0,0 +1,5 @@
+  o Minor bugfixes
+    - Avoid a double mark-for-free warning when failing to attach a
+      transparent proxy connection.  Fixes bug 2279.  Bugfix on
+      Tor 0.1.2.1 alpha.
+
diff --git a/src/or/connection.c b/src/or/connection.c
index 8a21d81c58..55a9557ef6 100644
--- a/src/or/connection.c
+++ b/src/or/connection.c
@@ -1178,7 +1178,8 @@ connection_handle_listener_read(connection_t *conn, int new_type)
   }
 
   if (connection_init_accepted_conn(newconn, conn->type) < 0) {
-    connection_mark_for_close(newconn);
+    if (! conn->marked_for_close)
+      connection_mark_for_close(newconn);
     return 0;
   }
   return 0;