MID server
Quick answer
What the MID server does, where to install it, how to size a cluster and how to keep it healthy.
Key takeaways
- MID servers make outbound connections only, no inbound firewall rules
- Use clusters for failover and load balancing
- ECC queue growth is the first sign of trouble
- Capabilities and IP ranges control job routing
Purpose
The MID server is a Java service that runs inside your network. It polls the instance over HTTPS for work, executes it locally, and posts results back. Nothing needs to be opened inbound through the firewall.
What runs on it
Discovery probes and patterns, Service Mapping, orchestration activities, integrations to internal systems, LDAP reads, and JDBC data sources. Capabilities and IP ranges decide which MID server picks up which job.
Sizing and health
Treat MID servers like any other server estate.
- Two MID servers per network zone gives you failover through a cluster
- Watch the ECC queue for growth, a backlog means the MID is undersized or offline
- Keep the service account permissions documented, they are audited
- MID servers auto upgrade with the instance, so plan a restart window
Want to learn this properly?
Our live, instructor-led ServiceNow Training covers this hands-on, with real projects and a certification path.
Check your understanding
How does a MID server receive work?
- A. The instance pushes over VPN
- B. It polls the instance over HTTPS
- C. Through SNMP traps
- D. By email
Show answer
B. It polls the instance over HTTPS
The MID server polls outbound, which avoids inbound firewall rules.
What indicates a MID server problem first?
- A. Slow forms
- B. Growing ECC queue backlog
- C. Missing notifications
- D. Failed logins
Show answer
B. Growing ECC queue backlog
Jobs pile up in the ECC queue when the MID is down or overloaded.