diff --git a/Shorewall/known_problems.txt b/Shorewall/known_problems.txt
index 9fedd4591..59114cbc1 100644
--- a/Shorewall/known_problems.txt
+++ b/Shorewall/known_problems.txt
@@ -21,6 +21,6 @@
     involving the IPv6 multicast network. The rules specify
     ff00::/10 where they should specify ff00::/8.  Also, rules
     instantiated when the IPv6 firewall is stopped use ff80::/10 rather
-    than fe80::/10.
+    than fe80::/10 (IPv6 link local network).