add availability note

Author: halkazwini

articles/web-application-firewall/ag/geomatch-custom-rules.md

@@ -5,7 +5,7 @@ author: halkazwini
 ms.author: halkazwini
 ms.service: azure-web-application-firewall
 ms.topic: concept-article
-ms.date: 04/30/2025
+ms.date: 05/12/2025
 ---
 
 # Geomatch custom rules
@@ -20,6 +20,9 @@ To create a geo-filtering custom rule in the Azure portal, select *Geo location*
 > [!IMPORTANT]
 > Include the country code **ZZ** whenever you use geo-filtering. The **ZZ** country code (or *Unknown* country/region) captures IP addresses that aren't yet mapped to a country or region in our dataset. This avoids false positives.
 
+> [!NOTE]
+> Geo-filtering custom rules are only supported in the Azure public cloud, Azure China, and Azure Government.
+
 ## Country/region codes
 
 If you're using the *geomatch* operator, the selectors can be any of the following two-digit country/region codes.