diff --git a/federation/README.md b/federation/README.md
index b32d145..152f8c2 100644
--- a/federation/README.md
+++ b/federation/README.md
@@ -97,6 +97,8 @@ respectively), and the system looks like this:
                    |               | Responder |                 |
                    |               +-----------+                 |
                    |                172.50.0.88                  |
+                   |            [fd23:d79:d076::88]              |
+                   |                                             |
                    |                                             |
                    +----------------172.50.0.0/24----------------+
                                 fd23:0d79:d076::/64