Merge pull request #290820 from siddomala/0ASN

0 ASN

Author: prmerger-automator[bot]

articles/route-server/troubleshoot-route-server.md

@@ -75,11 +75,15 @@ Although Azure VPN gateway can receive the default route from its BGP peers incl
 
 The ASN that the Route Server uses is 65515. Make sure you configure a different ASN for your NVA so that an *eBGP* session can be established between your NVA and Route Server so route propagation can happen automatically. Make sure you enable "multi-hop" in your BGP configuration because your NVA and the Route Server are in different subnets in the virtual network.
 
+### Why does connectivity not work when I advertise routes with an ASN of 0 in the AS-Path? 
+
+Azure Route Server drops routes with an ASN of 0 in the AS-Path. To ensure these routes are successfully advertised into Azure, the AS-Path should not include 0. 
+
 ### The BGP peering between my NVA and Route Server is up. I can see routes exchanged correctly between them. Why aren't the NVA routes in the effective routing table of my VM? 
 
 * If your VM is in the same virtual network as your NVA and Route Server:
 
-    Route Server exposes two BGP peer IPs, which are hosted on two VMs that share the responsibility of sending the routes to all other VMs running in your virtual network. Each NVA must set up two identical BGP sessions (for example, use the same AS number, the same AS path and advertise the same set of routes) to the two VMs so that your VMs in the virtual network can get consistent routing info from Azure Route Server.
+    Route Server exposes two BGP peer IPs, which share the responsibility of sending the routes to all other VMs running in your virtual network. Each NVA must set up two identical BGP sessions (for example, use the same AS number, the same AS path and advertise the same set of routes) to the two BGP peer IPs so that your VMs in the virtual network can get consistent routing info from Azure Route Server.
 
     :::image type="content" source="./media/troubleshoot-route-server/network-virtual-appliances.png" alt-text="Diagram showing a network virtual appliance (NVA) with Azure Route Server.":::
 

articles/virtual-wan/virtual-wan-faq.md

@@ -361,6 +361,10 @@ Enabling or disabling the toggle will only affect the following traffic flow: tr
 
 :::image type="content" source="./media/virtual-wan-expressroute-portal/expressroute-bowtie-virtual-network-virtual-wan.png" alt-text="Diagram of a standalone virtual network connecting to a virtual hub via ExpressRoute circuit." lightbox="./media/virtual-wan-expressroute-portal/expressroute-bowtie-virtual-network-virtual-wan.png":::
 
+### Why does connectivity not work when I advertise routes with an ASN of 0 in the AS-Path? 
+
+The Virtual WAN hub drops routes with an ASN of 0 in the AS-Path. To ensure these routes are successfully advertised into Azure, the AS-Path should not include 0. 
+
 ### Can hubs be created in different resource groups in Virtual WAN?
 
 Yes. This option is currently available via PowerShell only. The Virtual WAN portal requires that the hubs are in the same resource group as the Virtual WAN resource itself.