Merge pull request #211777 from greg-lindsay/atm-upd

add info about 500 error

Author: prmerger-automator[bot]

articles/traffic-manager/traffic-manager-FAQs.md

@@ -8,7 +8,7 @@ ms.service: traffic-manager
 ms.topic: article
 ms.tgt_pltfrm: na
 ms.workload: infrastructure-services
-ms.date: 01/31/2022
+ms.date: 09/19/2022
 ms.author: greglin 
 ms.custom: devx-track-azurepowershell
 ---
@@ -40,6 +40,12 @@ Further investigation should therefore focus on the application.
 
 The HTTP host header sent from the client's browser is the most common source of problems. Make sure that the application is configured to accept the correct host header for the domain name you’re using. For endpoints using the Azure App Service, see [configuring a custom domain name for a web app in Azure App Service using Traffic Manager](../app-service/configure-domain-traffic-manager.md).
 
+### How can I resolve a 500 (Internal Server Error) problem when using Traffic Manager?
+
+If your client or application receives an HTTP 500 error while using Traffic Manager, this can be caused by a stale DNS query. To resolve the issue, clear the DNS cache and allow the client to issue a new DNS query.
+
+When a service endpoint is unresponsive, clients and applications that are using that endpoint do not reset until the DNS cache is refreshed. The duration of the cache is determined by the time-to-live (TTL) of the DNS record. For more information, see [Traffic Manager and the DNS cache](traffic-manager-how-it-works.md#traffic-manager-and-the-dns-cache).
+
 ### What is the performance impact of using Traffic Manager?
 
 As explained in [How Traffic Manager Works](../traffic-manager/traffic-manager-how-it-works.md), Traffic Manager works at the DNS level. Since clients connect to your service endpoints directly, there’s no performance impact incurred when using Traffic Manager once the connection is established.

articles/traffic-manager/traffic-manager-how-it-works.md

@@ -4,12 +4,12 @@ description: This article will help you understand how Traffic Manager routes tr
 services: traffic-manager
 documentationcenter: ''
 author: greg-lindsay
-manager: twooley
+manager: kumud
 ms.service: traffic-manager
 ms.topic: article
 ms.tgt_pltfrm: na
 ms.workload: infrastructure-services
-ms.date: 03/05/2019
+ms.date: 09/19/2022
 ms.author: greglin
 ---
 
@@ -33,8 +33,8 @@ Contoso Corp have developed a new partner portal. The URL for this portal is `ht
 To achieve this configuration, they complete the following steps:
 
 1. Deploy three instances of their service. The DNS names of these deployments are 'contoso-us.cloudapp.net', 'contoso-eu.cloudapp.net', and 'contoso-asia.cloudapp.net'.
-1. Create a Traffic Manager profile, named 'contoso.trafficmanager.net', and configure it to use the 'Performance' traffic-routing method across the three endpoints.
-1. Configure their vanity domain name, 'partners.contoso.com', to point to 'contoso.trafficmanager.net', using a DNS CNAME record.
+2. Create a Traffic Manager profile, named 'contoso.trafficmanager.net', and configure it to use the 'Performance' traffic-routing method across the three endpoints.
+3. Configure their vanity domain name, 'partners.contoso.com', to point to 'contoso.trafficmanager.net', using a DNS CNAME record.
 
 ![Traffic Manager DNS configuration][1]
 
@@ -61,6 +61,8 @@ Continuing from the previous example, when a client requests the page `https://p
 7. The recursive DNS service consolidates the results and returns a single DNS response to the client.
 8. The client receives the DNS results and connects to the given IP address. The client connects to the application service endpoint directly, not through Traffic Manager. Since it is an HTTPS endpoint, the client performs the necessary SSL/TLS handshake, and then makes an HTTP GET request for the '/login.aspx' page.
 
+#### Traffic Manager and the DNS cache
+
 The recursive DNS service caches the DNS responses it receives. The DNS resolver on the client device also caches the result. Caching enables subsequent DNS queries to be answered more quickly by using data from the cache rather than querying other name servers. The duration of the cache is determined by the 'time-to-live' (TTL) property of each DNS record. Shorter values result in faster cache expiry and thus more round-trips to the Traffic Manager name servers. Longer values mean that it can take longer to direct traffic away from a failed endpoint. Traffic Manager allows you to configure the TTL used in Traffic Manager DNS responses to be as low as 0 seconds and as high as 2,147,483,647 seconds (the maximum range compliant with [RFC-1035](https://www.ietf.org/rfc/rfc1035.txt)), enabling you to choose the value that best balances the needs of your application.
 
 ## FAQs
@@ -73,6 +75,8 @@ The recursive DNS service caches the DNS responses it receives. The DNS resolver
 
 * [Why am I seeing an HTTP error when using Traffic Manager?](./traffic-manager-faqs.md#why-am-i-seeing-an-http-error-when-using-traffic-manager)
 
+* [How can I resolve a 500 (Internal Server Error) problem when using Traffic Manager?](./traffic-manager-faqs.md#how-can-i-resolve-a-500-internal-server-error-problem-when-using-traffic-manager)
+
 * [What is the performance impact of using Traffic Manager?](./traffic-manager-faqs.md#what-is-the-performance-impact-of-using-traffic-manager)
 
 * [What application protocols can I use with Traffic Manager?](./traffic-manager-faqs.md#what-application-protocols-can-i-use-with-traffic-manager)