With IPHost Network Monitor you can run simple snmp requests against a F5 Network device in your network.
globalLDnsDuration
global L Dns Duration
1.3.6.1.4.1.3375.1.2.1.1.1.59
Interval in seconds between checks of LDNS memory usage to determine whether to reap.
Back to F5-3DNS-MIB MIB page.
IPHost Network monitor allows you to monitor globalLDnsDuration on F5 Network device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring F5 Network ADC chassis right now.