Update README.md

README.md

@@ -41,6 +41,10 @@ You can click **Profile Settings** button on the left panel to change default ap
 
 ##  What are the IP addresses I should whitelist if I run services behind firewall?
 
+Note that code.stanford.edu does not have firewall on port 443, port 22 to restrict access to its console or through command line.
+
+If your system cannot access to it, you may need to do one of the followings:
+
 - **34.83.239.226**: GitLab instance's static NAT address. If you use webhooks to other services that
 is behind a firewall, you need to whitelist this NAT address.