diff --git a/ubuntu/networking.md b/ubuntu/networking.md
index e7e947d..5a01539 100644
--- a/ubuntu/networking.md
+++ b/ubuntu/networking.md
@@ -4,6 +4,8 @@ sudo nmap -T Aggressive -A -v 127.0.0.1 -p 1-10000
 
 sudo netstat --tcp --udp --listening --program
 
+lists programs with port numbers: `sudo netstat -tup`
+
 sudo lsof +M -i4 -i6
 
 let's encrypt certbot instructions for apache: