Merge pull request #239797 from vhorne/ddos-net-sec

add network security link

Author: prmerger-automator[bot]

articles/ddos-protection/ddos-protection-overview.md

@@ -82,3 +82,5 @@ For frequently asked questions, see the [DDoS Protection FAQ](ddos-faq.yml).
 
 * [Quickstart: Create a DDoS Protection Plan](manage-ddos-protection.md)
 * [Learn module: Introduction to Azure DDoS Protection](/training/modules/introduction-azure-ddos-protection/)
+* [Learn more about Azure network security](../networking/security/index.yml)
+