--- sourceDocument: Australia IT Operations Management sourceDocumentLink: https://www.servicenow.com/docs/r/australia/it-operations-management Release : - australia ft:locale : - en-US ft:publication_title : - Australia IT Operations Management ft:clusterId : - itom bundleId : - itom workflow : - Technology --- # Automatic MID Server selection # Automatic MID Server selection {#ariaid-title1} Release version: Australia Updated March 12, 2026 ![](https://www.servicenow.com/docs/portal-asset/ico-clock) 2 minutes to read Summarize ![AI sparkle icon](https://servicenow.com/docs/portal-asset/ai-sparkle-icon) Summarized using AI This content was generated using new OpenAI-powered functionality. Results are provided on an as is basis and are not guaranteed to be accurate or complete. ## Summary of Automatic MID Server selection Automatic MID Server selection in ServiceNow optimizes agent connections by enabling agents to dynamically select the most efficient available MID Server based on latency and current load. This feature, part of the Agent Client Collector (ACC), is disabled by default and primarily serves as a fail-over mechanism rather than a full load balancer. Show full answer Show less ## Key Features * **Dynamic Selection:** Agents perform connectivity tests against available MID Servers and choose the best connection automatically. * **Capability Filtering:** MID Server capabilities can restrict which servers an agent can connect to, improving connection relevance. * **Automatic Configuration Updates:** The back-end URL list on the agent host is kept up to date without manual workflows. * **Fail-over Support:** Agents maintain primary and secondary MID Server lists for seamless fail-over if connection issues occur. * **Unified Key Store:** Secure communication between MID Servers and agents is supported through the MID Server unified key store. ## Considerations for Use * This feature is not a true load balancer; for load balancing, a dedicated application load balancer is preferable. * Automatic MID Server selection introduces complexity in back-end URL configuration, as it derives from multiple sources. * Agents receive a list of all MID Servers listening for ACC connections, which can include servers in restricted zones, potentially triggering security alerts. * DNS configuration impacts agent connectivity; periodic DNS resolution and network changes (e.g., switching between corporate networks, Wi-Fi, VPN) may cause reconnection issues. ## How It Works When enabled, the ServiceNow instance periodically sends updates about available MID Servers to agents. Agents then select primary and secondary MID Servers, storing this information in their configuration files for connection management and fail-over. Upon detecting IP address changes, agents re-evaluate and connect to the most efficient MID Server available. ## Enabling and Configuration * Enable automatic MID Server selection to allow agents to conduct connectivity tests and select optimal MID Servers. * Configure MID Servers with Agent Client Collector capabilities; only those with matching capabilities are eligible for automatic selection. * Exclude specific MID Servers from automatic selection based on constraints such as firewall rules. ## Practical Impact for ServiceNow Customers Enabling automatic MID Server selection can reduce manual configuration efforts and improve agent connectivity efficiency. However, customers should carefully evaluate their network environments, security policies, and load balancing requirements before enabling this feature. Proper configuration ensures agents connect reliably to suitable MID Servers, enhancing performance and stability of the Agent Client Collector operations. Automatic selection of MID Servers ensures that each agent uses the most efficient available MID Server. The Agent Client Collector automatic MID Server selection feature set is disabled by default. There are several factors to consider before determining if automatic MID Server selection is right for your use cases. ## Use case considerations {#acc-auto-mid-selection__section_l2d_wyh_qzb} Automatic MID Server selection provides several benefits. [MID Server capabilities](https://www.servicenow.com/docs/access?context=t_ConfigureCapabilities&version=australia&pubname=australia-servicenow-platform§ion=r_MIDServerCapabilities&ft:locale=en-US) can narrow the list of MID Servers an agent can potential connect to. Automatic MID Server selection keeps the back-end URL configuration list up to date on the agent host without additional work flows. When automatic MID Server selection is enabled, the agent performs a connectivity test against the list of available MID Servers. The agent then determines the best connection based on latency and number of currently connected agents. However, there are several additional considerations that may make automatic MID Server selection wrong for your use case. The ACC automatic MID Server selection is not a true load balancer and should be considered a fail-over mechanism. There is higher complexity for choosing a back-end URL as it is derived from multiple input sources. If, instead, an application load balancer is used only one back-end URL needs to be specified. See [Enable the Agent Client Collector load balancer](https://www.servicenow.com/docs/rS1CnlCXliy8yS6IB2C4rQ "Enable a load balancer to ensure that you have functional MID Servers. A load balancer distributes resources over multiple MID Servers to ensure that no single MID Server is overloaded.") for more information. By default, each agent is sent the list of all MID Servers listening for ACC connections. Since that list includes MID Servers running in restricted areas, the agents can try to connect to them which can generate security alerts. Your DNS configuration should be considered before using automatic MID Server selection because the resolution can lead to unexpected results. The DNS resolution is done periodically. End User Compute systems that alternate between internal corporate, Wi-Fi, VPN, or external networks may not be able to reconnect if the network context has changed. ## Automatic selection process {#acc-auto-mid-selection__section_byl_xyh_qzb} When automatic selection is enabled, the ServiceNow instance sends periodic MID Server updates to existing agents. The agent selects a MID Server based on information it receives from the ServiceNow instance. During automatic MID Server selection, the agent selects a primary MID and a secondary MID list, and writes them to the agent's config file. The agent uses this list for fail-over protection when the primary MID/secondary MID in the list loses connection. When an agent detects that its IP address has changed, it automatically connects with the most efficient MID Server available from the agent's list of MID Servers. To secure communication between the MID Server and the agent, use the MID Server's unified key store. For details on using the MID Server unified key store, see [MID Server unified key store](https://www.servicenow.com/docs/access?context=mid-unified-keystore&version=australia&pubname=australia-servicenow-platform&ft:locale=en-US). * **[Enable automatic MID Server selection](https://www.servicenow.com/docs/U1g6QCasFCv6bQf0P2sT3A)** Enabling automatic MID Server selection lets the agent perform a connectivity test against the list of available MID Servers. The agent then determines the best connection based on latency and number of currently connected agents. Automatic MID Server selection is disabled by default. * **[Configure the Agent Client Collector capabilities for MID Servers](https://www.servicenow.com/docs/kTK9Bcl0ZVfMo18HTptKDw)** Configure the MID Servers with Agent Client Collector capabilities to enable the MID Servers to work with agents. Agents that have identical MID Server capabilities are eligible for automatic MID Server selection. * **[Configure the automatic MID Server selection based on the Agent Client Collector capabilities](https://www.servicenow.com/docs/D5D9KSUa0tUEZ5rbzPfqyg)** Configure the MID Servers that are ineligible for automatic MID Server selection with the agent. For example, you may want to block a MID Server from connecting to your agent due to firewall constraints. **Related tasks** * [Enable automatic MID Server selection](https://www.servicenow.com/docs/U1g6QCasFCv6bQf0P2sT3A "Enabling automatic MID Server selection lets the agent perform a connectivity test against the list of available MID Servers. The agent then determines the best connection based on latency and number of currently connected agents. Automatic MID Server selection is disabled by default.")