diff --git a/README.md b/README.md
index 1ecbb23..601bcbf 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,8 @@
 # Randort
 The shell script to generate a random user port number
+
+> Port numbers are assigned in various ways, based on three ranges: System
+> Ports (0-1023), User Ports (1024-49151), and the Dynamic and/or Private
+> Ports (49152-65535)
+
+[Reference](https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml)