Failure Symptoms and Solutions | NETGEAR NMS100 manual

Reference Manual for the ProSafe Network Management System NMS100

The figure below shows a sample top-level and subnet Map view for a small network. Note that some devices have vendor-specific icons while others have generic icons. Each generic device icon is marked as SNMP or ICMP (Ping), which is important in determining discovery problems.

Figure 5-1: Sample top-level and Subnet Map views for a small network

Failure Symptoms and Solutions

The discovery agent uses a heuristic algorithm to find network devices. That means it is somewhat non-deterministic and will show different results from one run to another. There are many reasons for this, including lost broadcast responses such as buffer overflows, collisions, lost polls, and slow responses. This is completely normal. However, there are some permanent failure cases that you can resolve. The following symptoms are typical of a discovery failure:

1.Nothing added to the map (after a suitable wait period of several minutes).

2.Top-level map only or mostly contains subnet icons, with no links.

3.Some or all SNMP devices are added to lower level subnets as Ping icons.

4.Not all expected network devices are discovered.

The following sections describe solutions to these problems.

5-2	Troubleshooting and Advanced Configuration

September 2004 202-10058-01

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NETGEAR NMS100 manual Failure Symptoms and Solutions, Sample top-level and Subnet Map views for a small network

Contents

September 2004 NETGEAR, Inc Customer Support World Wide Web TrademarksStatement of Conditions Contents Chapter Data and Statistics Appendix a Contents Manual Scope Audience, Scope, Conventions, and FormatsTypographical Conventions Other ProSafe NMS Features Overview System Requirements Device Access ModesProSafe Network Management System Recommended system requirements Package Contents Introduction Introduction Chapter Installation and Startup Installing the ProSafe NMS Server and Local Console Installing the Air Messenger Pro Paging Software Starting the ProSafe NMS Server and Local Console Stopping and Starting the Server Disabling Automatic Console LoginStarting a Local Console Session Event Log Tool Console ElementsMain button bar Edit button bar Selection Tool Element Function Console Button Commands Zoom to Selection Tool tabs Selection ToolEvent Log Tool Selection Tab Description View Window Area Installation and Startup Working with the Map Database Map Selection Tree Zoom Using Map View WindowsView All Zoom Out Rectangle Moving Map Objects Moving Objects at the Root Level Moving Objects Inside Subnet Levels Automatically arranged and manually arranged submap levels Moving Objects from One Subnet to Another Changing Object Properties Attributes Attribute Name Description Access ParametersObject Properties Access tab Type-Dependent Attributes Object Properties Attribute tab Object Attribute Name Description Type a Type Description Adding Map ObjectsObject Types Manage Menus Viewing Device MIB DataMIB Selection Tree Table Display Elements Custom Menus Graph Display Elements Graph Styles Saving Long-term Statistics Creating a New Report Viewing Trend Data in a Graph Window Limiting Saved Instances Alarm Type Description Setting Threshold AlarmsThreshold Alarms Setting Status Variable Polling Configuring Automatic Alarms Setting Manual Threshold Alarms TCP Service Polling Polling TCP Application ServicesDiscovery of Four Built-in Services Custom TCP Service Polling Managing Polling for the Device Emailing or Paging the Administrator on an Event To modify an existing Custom TCP Service definition Then, set the Email/Paging global event options Add an Event Filter for the pollDeviceDown event Then, set the Email/Page event actions Event Subtree Trap Name Description Other Event TypesProSafe NMS Events Emailing or Paging Multiple Users First, add a grouped set of users Then, add an Event Filter for the selected devices Normal Discovery Map Layout Troubleshooting Network DiscoveryDuration of Network Discovery Failure Symptoms and Solutions Sample top-level and Subnet Map views for a small network Discovery Agent Fails to Connect to the Server Incorrect or Missing Community Names Not Enough Seeds Snmp Device Access Control ListFirewalls Block Snmp Operations Limiting the Scope of Discovery Setting Up New FiltersBroadcast Packet Losses Stopping Discovery Auto-Layout Event Description Parameters Event ParametersEvent Parameters Set Community name of the target device List of Glossary Terms Cat Denial of Service attackAuto Uplink Dynamic Host Configuration Protocol Domain Name DoS Internet Protocol GatewayIP Address MAC address Lightweight Directory Access ProtocolLocal area network Mbps Packet NetBIOSNetwork Address Translation Perfect Forward Secrecy PPP over Ethernet PPPoEPPP over ATM Router Subnet Mask WEB Proxy Server Wi-Fi Windows Internet Naming ServiceUniversal Plug and Play Wide area network Wireless Network Name Ssid Index Index Index