Merge pull request #281753 from alt-key/patch-7

add prereq for dr script

Author: prmerger-automator[bot]

articles/azure-arc/system-center-virtual-machine-manager/disaster-recovery.md

@@ -26,6 +26,13 @@ To recover from Arc resource bridge VM deletion, you need to deploy a new resour
 >[!Note]
 > DHCP-based Arc Resource Bridge deployment is no longer supported.<br><br>
 If you had deployed Arc Resource Bridge earlier using DHCP, you must clean up your deployment by removing your resources from Azure and do a [fresh onboarding](./quickstart-connect-system-center-virtual-machine-manager-to-arc.md).
+>
+## Prerequisites
+
+1. The disaster recovery script must be run from the same folder where the config (.yaml) files are present. The config files are present on the machine used to run the script to deploy Arc resource bridge. 
+
+1. The machine being used to run the script must have bidirectional connectivity to the Arc resource bridge VM on port 6443 (Kubernetes API server) and 22 (SSH), and outbound connectivity to the Arc resource bridge VM on port 443 (HTTPS).
+
 
 ### Recover Arc resource bridge from a Windows machine
 
@@ -60,4 +67,4 @@ If the recovery steps mentioned above are unsuccessful in restoring Arc resource
 
 - Get answers from Azure experts through [Microsoft Q&A](/answers/topics/azure-arc.html).
 - Connect with [@AzureSupport](https://twitter.com/azuresupport), the official Microsoft Azure account for improving customer experience. Azure Support connects the Azure community to answers, support, and experts.
-- [Open an Azure support request](../../azure-portal/supportability/how-to-create-azure-support-request.md).
+- [Open an Azure support request](../../azure-portal/supportability/how-to-create-azure-support-request.md).