diff --git a/book/chapter-06-gbapp-reference.md b/book/chapter-06-gbapp-reference.md
index e15cd408..bf2d2ff0 100644
--- a/book/chapter-06-gbapp-reference.md
+++ b/book/chapter-06-gbapp-reference.md
@@ -92,6 +92,12 @@ npm -v
 
 ```
 
+Opening 443 Port in Linux
+```
+sudo setcap 'cap_net_bind_service=+ep' /usr/local/bin/node
+sudo setcap 'cap_net_bind_service=+ep' `which node`
+```
+
 Additional Infrastructure 
 ```
 sudo apt-get install libxtst-dev