ISPPlanet • Budget Network Management System Series - Wrap-Up

Network Discovery
After installation, most SNMP managers begin with discovery, using probes to locate and identify every device in the network to be managed. NetPlus AutoManager and SNMP ToolChest only discover devices that speak SNMP. All others can discover any device that answers an ICMP ping. WhatsUp Gold and SNMPc use more sophisticated router-based methods to speed discovery in larger networks.

Vendor	ACE*COMM	MediaHouse	SNMP ToolChest Company	MG-SOFT	Ipswitch	Castle Rock Computing
Product	NetPlus AutoManage	ipMonitor	SNMP ToolChest	NetInspector LITE *	WhatsUp Gold	SNMPc
Networks	IP, IPX	IP	IP	IP	IP, IPX, NetBIOS	IP, IPX
Discovery methods	SNMP	Ping, Port scan	Ping-assisted SNMP	SNMP or Ping	Seed router Ping, TraceRoute SNMP, or NetBIOS Port scan	Seed router SNMP or PingPort scan
Initiated	Manually	Manually	Manually	At startup, Scheduled, Manually	Manually	At startup, Scheduled, Manually
Search based on	IP Range, Timeout	Subnet/Host address, Port list	Subnet list	IP Range, Timeout	Subnet/Host address, Root device, Span, Depth, Hops. Timeout, Port list	Subnet list, Routers, Port list
Can be incremental	Yes	Yes	No (but can compare prior results)	Yes	No	Yes
Text output	No	Yes	Yes	Yes	Yes	Yes
Map output	Yes	No	No	Yes	Yes	Yes
Auto-layout	No	No	No	Yes	Yes	Yes

* MG-SOFT MIB Browser Professional network discovery performed independently and does not generate topology map.

Several products can discover services running on devices by scanning for listening ports. But even well-intentioned port scans can trigger intrusion detection and firewall alarms and must be used with care. Port scanning is appropriate when you plan to use the NMS for service-level monitoring. Limiting discovery by IP address range or subnet can avoid searching networks that you don't own or control. WhatsUp Gold offers the most discovery flexibility—it can even discover hosts in a Windows network using NetBIOS.

Two products did not plot discovery results on a topology map: ipMonitor and SNMP ToolChest. The others used discovery to populate maps, typically as a hierarchy of connected subnets. Hierarchies are important because they enable visual "bubble up" status monitoring. A root map provides an eagle-eye view, while subordinate maps are used to drill down and isolate problems. Although ipMonitor does not provide a topology map, it can accomplish "bubble up" status monitoring through administrator-defined Groups.

Finally, few networks are static. Devices come and go and get swapped out. New services are added, sometimes without authorization. Knowing what your network contains on any day can be a challenge. Products that support incremental, scheduled discovery make maps much easier to maintain.

Pt. 1: Introduction / What We Tested	Pt. 5: Device Control
Pt. 2: Installation & Setup <	Pt. 6: Network Montoring & Alerts
Pt. 3: Network Discovery	Pt. 7: Reporting
> Pt. 4: SNMP Browse and Query	Pt. 8: Product Support / Overall Evaluation