NETGEAR NMS100 Broadcast Packet Losses, Limiting the Scope of Discovery, Setting Up New Filters

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Reference Manual for the ProSafe Network Management System NMS100

Broadcast Packet Losses

In many cases network discovery mostly works but you do not see as many devices as you expect. As many devices are not represented in SNMP ARP tables they can only be discovered with broadcasts. Broadcasts responses can be lost due to buffer overflows or collisions.

To get around this problem you can enable sequential polling of every possible address within a discovered subnet. Use the Config/Discovery-Polling menu and select the Ping Scan Subnets check box then click the Restart button.

Note that ProSafe NMS will not poll ranges that you specify, but only discovered subnets. To discover more subnets, add more seeds as described in the previous section.

Limiting the Scope of Discovery

If you have a large network but you only want to manage a small part of it, you need to set discovery address range filters. Discovery filters only specify what should be included. So if you set any discovery filters you must set enough of them to cover any address ranges you want to discover.

Address range filters are in dot notation with optional wild-card asterisk characters and numeric range specifiers. Unless the last element is an asterisk, there must be four dot-separated elements. The following are some valid examples:

207.* 207.212.33.* 207.100-211.* 198.*.*.22-88

Setting Up New Filters

1.Use the Config/Discovery-Polling menu.

2.Select your system address from the agents list.

3.Click the Filters tab.

4.Enter a filter in the Address Range edit box and click Add.

5.Repeat for other filters.

6.Click OK.

Troubleshooting and Advanced Configuration

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September 2004 202-10058-01

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Contents NETGEAR, Inc September 2004Customer Support World Wide Web TrademarksStatement of Conditions Contents Chapter Data and Statistics Appendix a Contents Manual Scope Audience, Scope, Conventions, and FormatsTypographical Conventions Overview Other ProSafe NMS FeaturesProSafe Network Management System Device Access ModesSystem Requirements Recommended system requirementsPackage Contents Introduction Introduction Installing the ProSafe NMS Server and Local Console Chapter Installation and StartupStarting the ProSafe NMS Server and Local Console Installing the Air Messenger Pro Paging SoftwareStopping and Starting the Server Disabling Automatic Console LoginStarting a Local Console Session Main button bar Edit button bar Selection Tool Console ElementsEvent Log Tool Element FunctionZoom to Console Button CommandsEvent Log Tool Selection ToolSelection Tool tabs Selection Tab DescriptionView Window Area Installation and Startup Map Selection Tree Working with the Map DatabaseView All Zoom Out Using Map View WindowsZoom RectangleMoving Objects at the Root Level Moving Map ObjectsAutomatically arranged and manually arranged submap levels Moving Objects Inside Subnet LevelsMoving Objects from One Subnet to Another Attributes Changing Object PropertiesAttribute Name Description Access ParametersObject Properties Access tab Type-Dependent Attributes Object Attribute Name Description Type a Object Properties Attribute tabType Description Adding Map ObjectsObject Types Manage Menus Viewing Device MIB DataMIB Selection Tree Custom Menus Table Display ElementsGraph Styles Graph Display ElementsCreating a New Report Saving Long-term StatisticsViewing Trend Data in a Graph Window Limiting Saved Instances Alarm Type Description Setting Threshold AlarmsThreshold Alarms Configuring Automatic Alarms Setting Status Variable PollingSetting Manual Threshold Alarms TCP Service Polling Polling TCP Application ServicesDiscovery of Four Built-in Services Managing Polling for the Device Custom TCP Service PollingTo modify an existing Custom TCP Service definition Emailing or Paging the Administrator on an EventThen, 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 First, add a grouped set of users Emailing or Paging Multiple UsersThen, add an Event Filter for the selected devices Normal Discovery Map Layout Troubleshooting Network DiscoveryDuration of Network Discovery Sample top-level and Subnet Map views for a small network Failure Symptoms and SolutionsIncorrect or Missing Community Names Discovery Agent Fails to Connect to the ServerNot 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 Domain Name DoS Dynamic Host Configuration ProtocolInternet Protocol GatewayIP Address Local area network Lightweight Directory Access ProtocolMAC address MbpsNetwork Address Translation NetBIOSPacket Perfect Forward SecrecyPPP over ATM PPPoEPPP over Ethernet RouterSubnet Mask Universal Plug and Play Wi-Fi Windows Internet Naming ServiceWEB Proxy Server Wide area networkWireless Network Name Ssid Index Index Index