Merge pull request #233794 from greg-lindsay/appgw-upd

SEO and some edits

Author: v-shils

articles/application-gateway/multiple-site-overview.md

@@ -1,10 +1,10 @@
 ---
 title: Hosting multiple sites on Azure Application Gateway
-description: This article provides an overview of the Azure Application Gateway multi-site support.
+description: This article provides an overview of the Azure Application Gateway multi-site support. Examples are provided of rule priority and the order of evaluation for rules applied to incoming requests. Conditions and limitations for using wildcard rules are described.
 services: application-gateway
 author: greg-lindsay
 ms.service: application-gateway
-ms.date: 10/03/2022
+ms.date: 04/07/2023
 ms.author: greglin
 ms.topic: conceptual
 ---
@@ -18,34 +18,32 @@ You can also define wildcard host names in a multi-site listener and up to 5 hos
 :::image type="content" source="./media/multiple-site-overview/multisite.png" alt-text="Multi-site Application Gateway":::
 
 > [!IMPORTANT]
-> Rules are processed in the order they are listed in the portal for the v1 SKU. For v2 SKU use [rule priority](#request-routing-rules-evaluation-order) to specify the processing order. It is highly recommended to configure multi-site listeners first prior to configuring a basic listener.  This will ensure that traffic gets routed to the right back end. If a basic listener is listed first and matches an incoming request, it gets processed by that listener.
+> Rules are processed in the order they are listed in the portal for the v1 SKU. For v2 SKU use [rule priority](#request-routing-rules-evaluation-order) to specify the processing order. It is highly recommended to configure multi-site listeners first prior to configuring a basic listener.  This ensures that traffic gets routed to the right back end. If a basic listener is listed first and matches an incoming request, it gets processed by that listener.
 
 Requests for `http://contoso.com` are routed to ContosoServerPool, and `http://fabrikam.com` are routed to FabrikamServerPool.
 
 Similarly, you can host multiple subdomains of the same parent domain on the same application gateway deployment. For example, you can  host `http://blog.contoso.com` and `http://app.contoso.com` on a single application gateway deployment.
 
 ## Request Routing rules evaluation order
 
-When you use multi-site listeners to ensure that the client traffic is routed to the accurate backend, it's important to have the request routing rules be present in the correct order.
-For example, if you have 2 listeners with associated Host name as `*.contoso.com` and `shop.contoso.com` respectively, the listener with the `shop.contoso.com` Host name would have to be processed before the listener with `*.contoso.com`. If the listener with `*.contoso.com` is processed first, then no client traffic would be received by the more specific `shop.contoso.com` listener.
+When you use multi-site listeners to ensure that the client traffic is routed to the accurate backend, it's important that the request routing rules are present in the correct order.
+For example, if you have 2 listeners with associated host names of `*.contoso.com` and `shop.contoso.com`, the listener with the `shop.contoso.com` host name must be processed before the listener with `*.contoso.com`. If the listener with `*.contoso.com` is processed first, then no client traffic is received by the more specific `shop.contoso.com` listener.
 
-This ordering can be established by providing a 'Priority' field value to the request routing rules associated with the listeners. You can specify an integer value from 1 to 20000 with 1 being the highest priority and 20000 being the lowest priority. In case the incoming client traffic matches with multiple listeners, the request routing rule with highest priority will be used for serving the request. Each request routing rule needs to have a unique priority value.
+The ordering of rules can be established by providing a **Priority** field value to the request routing rules associated with the listeners. You can specify an integer value from 1 to 20000 with 1 being the highest priority and 20000 being the lowest priority. If incoming client traffic matches with multiple listeners, the request routing rule with highest priority is used to serve the request. Each request routing rule must have a unique priority value.
 
 The priority field only impacts the order of evaluation of a request routing rule, this wont change the order of evaluation of path based rules within a `PathBasedRouting` request routing rule.
 
->[!NOTE]
->If you wish to use rule priority, you will have to specify rule priority field values for all the existing request routing rules. Once the rule priority field is in use, any new routing rule that is created would also need to have a rule priority field value as part of its config.
-Starting with API version 2021-08-01 rule priority field would be a mandatory field as part of the request routing rules.
-From this API version, rule priority field values would be auto-populated for existing request routing rules based on current ordering of evaluation as part of the first PUT call. Any future updates to request routing rules would need to have the rule priority field provided as part of the configuration.
+> [!NOTE]
+> To use rule priority, you must specify rule priority field values for all the existing request routing rules. Once the rule priority field is in use, any new routing rule that is created must have a rule priority field value as part of its configuration. 
 
 > [!IMPORTANT]
-> Rule priority field values for existing request routing rules based on current order would be automatically populated if any configuration updates are applied using API version 2021-08-01 and above, portal, Azure PowerShell and Azure CLI. Any future updates to request routing rules would need to have the rule priority field provided as part of the configuration.  
+>  Starting with API version 2021-08-01, the rule priority field is a mandatory field in the request routing rules. Rule priority field values for existing request routing rules, based on current ordering of evaluation as part of the first PUT call, are automatically populated if any configuration updates are applied using API version 2021-08-01 and above, portal, Azure PowerShell and Azure CLI. Future updates to request routing rules must have the rule priority field provided as part of the configuration.
 
 ## Wildcard host names in listener
 
 Application Gateway allows host-based routing using multi-site HTTP(S) listener. Now, you can use wildcard characters like asterisk (*) and question mark (?) in the host name, and up to 5 host names per multi-site HTTP(S) listener. For example, `*.contoso.com`.
 
-Using a wildcard character in the host name, you can match multiple host names in a single listener. For example, `*.contoso.com` can match with `ecom.contoso.com`, `b2b.contoso.com` and `customer1.b2b.contoso.com` and so on. Using an array of host names, you can configure more than one host name for a listener, to route requests to a backend pool. For example, a listener can contain `contoso.com, fabrikam.com` which will accept requests for both the host names.
+Using a wildcard character in the host name, you can match multiple host names in a single listener. For example, `*.contoso.com` can match with `ecom.contoso.com`, `b2b.contoso.com` and `customer1.b2b.contoso.com` and so on. Using an array of host names, you can configure more than one host name for a listener, to route requests to a backend pool. For example, a listener can contain `contoso.com, fabrikam.com` which accepts requests for both the host names.
 
 :::image type="content" source="./media/multiple-site-overview/wildcard-listener-diag.png" alt-text="Wildcard Listener":::
 
@@ -86,7 +84,7 @@ In the Azure portal, under the multi-site listener, you must choose the **Multip
     * If it's a wildcard hostname like *.contoso.com, you must upload a wildcard certificate with CN like *.contoso.com
     * If multiple host names are mentioned in the same listener, you must upload a SAN certificate (Subject Alternative Names) with the CNs matching the host names mentioned.
 * You can't use a regular expression to mention the host name. You can only use wildcard characters like asterisk (*) and question mark (?) to form the host name pattern.
-* For backend health check, you can't associate multiple [custom probes](application-gateway-probe-overview.md) per HTTP settings. Instead, you can probe one of the websites at the backend or use "127.0.0.1" to probe the localhost of the backend server. However, when you're using wildcard or multiple host names in a listener, the requests for all the specified domain patterns will be routed to the backend pool depending on the rule type (basic or path-based).
+* For backend health check, you can't associate multiple [custom probes](application-gateway-probe-overview.md) per HTTP settings. Instead, you can probe one of the websites at the backend or use "127.0.0.1" to probe the localhost of the backend server. However, when you're using wildcard or multiple host names in a listener, the requests for all the specified domain patterns are routed to the backend pool depending on the rule type (basic or path-based).
 * The "hostname" property takes one string as input, where you can mention only one non-wildcard domain name. The "hostnames" property takes an array of strings as input, where you can mention up to 5 wildcard domain names. Both these properties can't be used at once.
 
 See [create multi-site using Azure PowerShell](tutorial-multiple-sites-powershell.md) or [using Azure CLI](tutorial-multiple-sites-cli.md) for the step-by-step guide on how to configure wildcard host names in a multi-site listener.
@@ -103,7 +101,7 @@ There are three common mechanisms for enabling multiple site hosting on the same
 
 Currently Application Gateway supports a single public IP address where it listens for traffic. So multiple applications, each with its own IP address is currently not supported.
 
-Application Gateway supports multiple applications each listening on different ports, but this scenario requires the applications to accept traffic on non-standard ports.
+Application Gateway supports multiple applications each listening on different ports, but this scenario requires the applications to accept traffic on nonstandard ports.
 
 Application Gateway relies on HTTP 1.1 host headers to host more than one website on the same public IP address and port. The sites hosted on application gateway can also support TLS offload with Server Name Indication (SNI) TLS extension. This scenario means that the client browser and backend web farm must support HTTP/1.1 and TLS extension as defined in RFC 6066.