diff --git a/engine/userguide/networking/default_network/dockerlinks.md b/engine/userguide/networking/default_network/dockerlinks.md
index b0584cb0fa..49259c853a 100644
--- a/engine/userguide/networking/default_network/dockerlinks.md
+++ b/engine/userguide/networking/default_network/dockerlinks.md
@@ -21,7 +21,10 @@ detail on container linking in default `bridge` network.
 >**Warning**: The `--link` flag is a deprecated legacy feature of Docker. It may eventually
 be removed. Unless you absolutely need to continue using it, we recommend that you use
 user-defined networks to facilitate communication between two containers instead of using
-`--link`. 
+`--link`. One feature that user-defined networks do not support that you can do
+with `--link` is sharing environmental variables between containers. However,
+you can use other mechanisms such as volumes to share environment variables
+between containers in a more controlled way.
 
 ## Connect using network port mapping