diff --git a/docs/HowToAddABuilder.rst b/docs/HowToAddABuilder.rst
index 08cbecdc2a5..201c71b2139 100644
--- a/docs/HowToAddABuilder.rst
+++ b/docs/HowToAddABuilder.rst
@@ -62,6 +62,9 @@ Here are the steps you can follow to do so:
                     lab.llvm.org:9990 \
                     <buildslave-access-name> <buildslave-access-password>
 
+   To point a slave to silent master please use lab.llvm.org:9994 instead
+   of lab.llvm.org:9990.
+
 #. Fill the buildslave description and admin name/e-mail.  Here is an
    example of the buildslave description::