With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
ciscoUnityLicSecondServerIsLic
cisco Unity Lic Second Server Is Lic
1.3.6.1.4.1.9.9.385.1.2.20
This indicates whether or not a secondary (failover) server is licensed.
Back to CISCO-UNITY-MIB MIB page.
IPHost Network monitor allows you to monitor ciscoUnityLicSecondServerIsLic on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco switches right now.
