OpenNMS has the ability to poll the following services out-of-the-box:

openNMS monitors more than 30 services, including HTTP and HTTPS, DNS, DHCP, Citrix, Radius, ICMP (Ping). By default, it tests each service every 5 minutes, which is similar to other network management products.

openNMS also has an interesting feature called a downtime model, in which it can change its polling frequency when it detects an outage. In this case openNMS will increase his polling interval to 30 seconds when it detects an outage. However, after 5 minutes it goes back to a 5-minute cycle.