Keeping Tabs on Your Network First, a Horror Story Types of Management Tools What is SNMP? Dartmouth’s Net Management InterMapper demo Questions Rich Brown Dartware, LLC 20 May 2005

A Horror Story What happened… How could it have been prevented?

What is Network Management? A set of tools that: –Help you know what’s happening in your net –Help you administer your network –Make you look good with your customers... –By actually doing a good job

Network Management System Monitoring System Servers Routers & Switches Switches Wireless gear EnvironmentalSensors Power Systems , Pagers & Sounds & Sounds Web Pages/ Remote Views Strip Charts Diagram of the network network Log Files

Types of Management Tools Fault Management Configuration Management Security Management Performance Management Accounting Management Asset Management Planning Management Content Management

What is SNMP? SNMP is a protocol (set of rules) for conveying management or status information from devices such as servers, workstations, routers, switches, radios and other gear to a management station. Two ways to get data from a device –Management station “pulls” data from a device being tested (the SNMP Agent) –Agent “pushes” a trap to the management station The data values are defined by a MIB

What’s a MIB? “Management Information Base” MIB defines the kinds of data a device tracks MIBs for various devices –Router or Switch: traffic (packet & byte counts) & error counts (receive, transmit, discards, etc) –Web Server MIB shows pages served, 404s, 401s, etc. –Mail Server MIB shows messages processed, queue lengths –Environmental sensors: temperatures, switch closures, water on floor, door alarm, others –Typical Radio MIB: RSL, BER, number of subscribers, bandwidth, inside/outside temperature, etc.

What’s an OID? “Object Identifier” The “name” of the variable Always starts with … – … for standardized MIBs – … for vendor specific MIBs

Four Basic SNMP Operations –Get Retrieves the value of a MIB variable stored on the agent machine (gauge, counter, string, or address of another MIB variable) –GetNext Retrieves the value of the “next” MIB variable –Set Changes the value of a MIB variable –Trap An unsolicited notification sent by an agent to a management application (typically a notification of something unexpected, like an error)

Traps Traps are unsolicited reports that are sent to a management system by an SNMP agent process When an interesting event occurs, an agent generates a trap message and sends it to a designated network address Many events can be configured to signal a trap, like a network cable fault, failing NNIC of hard drive, a general protection fault, or a power supply failure

Ports & UDP SNMP uses User Datagram Protocol (UDP) as the transport mechanism for SNMP messages Like FTP, SNMP uses two well-known ports to operate: –UDP Port 161 SNMP Get/Set Messages –UDP Port 162 SNMP Trap Messages

Advantages of using SNMP Standardized Widely supported by many vendors Distributed management access Lightweight protocol

SNMP Management Solutions Open Source –Nagios, Big Brother, MRTG, perl scripts Commercial SMB –InterMapper, WhatsUp Gold, IPMonitor Commercial Enterprise –OpenView, Tivoli, Unicenter, BMC Patrol

Dartmouth’s Net Management A variety of tools... –InterMapper –Aruba wireless monitoring tools –Spam filtering –NAT for entire campus

InterMapper Demo InterMapper is a fault management tool Monitors network equipment and servers 24x7 to alert the manager about troubles Some performance management tools Get a demo from

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Bonus Slides These slides didn’t fit into the presentation, but we kept them for your information...

Why is it Important? To give Good Service and be professional A management system helps you to: –Know about problems before the phone rings –Know how your network’s configured—documentation –Know how your network is operating –Know about network limits before you hit the wall You can start small –Fault and Performance Management are critical –Implement other tools as your network grows

Types of Network Management Fault Management: Reactive and proactive network fault management Performance Management: Number of packets dropped, timeouts, collisions, CRC errors, response times Configuration Management: Inventory, configuration, provisioning Planning Management: Analysis of trends to help justify a network upgrade or a bandwidth increase Security Management: SNMP doesn't provide much here Accounting Management: Cost management and chargeback assessment Asset Management: Statistics of equipment, facility and administration personnel

Benefits of using SNMP Vendor Neutral Tools for Monitoring Universal Support Monitor lots of interesting information

Client Pull & Server Push SNMP is a client “pull” model –The management system (client) “pulls” data from the agent (server) SNMP also provides “server push” model –The agent (server) “pushes” out a trap message to a (client) management system

Fault Management Discover that a problem exists Notify the responsible parties Isolate the problem; show what is working Possibly fix the problem

Configuration Management Configure critical devices consistently –e.g. Routers and Servers Take inventory of important software on workstations Update computers automatically

Security Management Controlling access to information on the network Setting up accounts; testing passwords Firewalls & Intrusion Detection Systems

Performance Management Collecting and analyzing data about use Setting thresholds for alarms Simulating alternatives to find maximum performance Study trends and make predictions

Accounting Management Tracking individual or group use of network resources Billing for use Controlling use of network

Stand-alone vs. Platform Stand-alone programs solve specific problems; can be well-targeted and inexpensive; usually are easy to set up; but often duplicate notification, logging, databases, etc. Platforms provide base services plus plug-in modules; unified notifications, logging, databases; but can be very expensive to buy and hard to set up

Which ones do I need? Everyone needs security management tools: at least a firewall and access control –This will become true at your home when you get cable modem or DSL service Fault management tools give timely warnings For the other tools, it depends…