diff --git a/matrix/synapse/workers.md b/matrix/synapse/workers.md
index c84eec7..2711e12 100644
--- a/matrix/synapse/workers.md
+++ b/matrix/synapse/workers.md
@@ -97,3 +97,16 @@ Their configuration goes into `/etc/matrix-synapse/workers`, which we have to
 create first.
 
 
+# Preparing for sockets
+
+Because we use sockets for speed, we should make sure only those programs that
+need access to those sockets get it.
+
+Create a new group and add the users that need access to it:
+
+```
+addgroup --system clubmatrix
+addgroup matrix-synapse clubmatrix
+addgroup www-data clubmatrix
+```
+