Configure Simple Network Management Protocol (SNMP) Community Strings on a Router
Introduction      Overview      Requirements      Connect to the Router      Configure SNMP Community Strings on a Router           Enable SNMP Community Strings           Verify SNMP Community Strings           Modify SNMP Community Strings      Next Step      Troubleshoot the Procedure      Related Information	Download PDF   Configure Simple Network Management Protocol (SNMP) Community Strings on a Router

Introduction

This document explains how to configure Simple Network Management Protocol (SNMP) community/authenticating strings on Cisco routers.

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Overview

The Simple Network Management Protocol (SNMP) is an application layer protocol that facilitates the exchange of management information between network devices.

SNMP enables network administrators to manage network performance, find and solve network problems, and plan for network growth.

An SNMP community string is a text string that acts as a password. It is used to authenticate messages that are sent between the management station, the SNMP manager or Network management server like Cisco Works and the SNMP agent like Router or Switch. The community string is included in every packet that is transmitted between the SNMP manager and the SNMP agent.

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Requirements

To perform the steps described in this document, you need to have these items:

• Cisco Router that is powered on and running Cisco IOS Software

• You must have completed the initial configuration in Configure Your Router with Security Device Manager.

• A console cable. For more information about cables, refer to Cable Descriptions.

• Terminal emulation software such as HyperTerminal

  Note: For more information about how to create a terminal connection, refer to Create a HyperTerminal Connection.

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Connect to the Router

Follow these steps to connect to the router command line interface:

1. Connect a PC to the router with a console cable.

2. Create a HyperTerminal connection to your router. For more information, refer to Create a HyperTerminal Connection.

3. Log into the router with the login and password that you entered in fields B10 and B11 of the Router Worksheet.

   Username:admin
   Password:

   Note: If you do not know the password for your router, refer to Reset the Password on the Router.

4. Type enable and press Enter to access the privileged mode. Type the enable password that you entered in field B12 of the Router Worksheet and press Enter.

   Router>enable
   Password:
   Router#

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Configure SNMP Community Strings on a Router

Enable SNMP Community Strings

Follow these steps to enable SNMP community strings on your router:

1. Type show running-config and press Enter to look for the SNMP information.

   Router#show running-config
   Building configuration...
   Current configuration : 2937 bytes!
   version 12.4
   service timestamps debug datetime msec
   service timestamps log datetime msec
   service password-encryption
   !--- Output is suppressed for brevity.
   

   Note: If no SNMP information is present, continue the steps. If any SNMP commands are listed, you can modify or disable them in the section Modify SNMP Community Strings.

2. Type configure terminal and press Enter to enter the router configuration mode.

   Router#configure terminal
   Router(config)#
   

3. Type snmp-server community public RO to enable the Read-only (RO) community string where "public" is the Read-only community string.

   Router(config)#snmp-server community public RO
   

4. Type snmp-server community private RW to enable the Read-write (RW) community string:

   Router(config)#snmp-server community private RW

   where "private" is the Read-write community string.

5. Type exit and press Enter.

   Router(config)#exit
   Router#
   

6. Type write memory and press Enter.

   Router#write memory
   

Verify SNMP Community Strings

Follow these steps to verify SNMP community strings:

1. Verify that there is TCP/IP connectivity between the Network Management Server (NMS) server and the router. On the command prompt of your PC which runs a NMS type, ping followed by IP address of the router configured with SNMP community strings.

   C:\>ping 192.168.10.1
   
   Pinging 192.168.10.1 with 32 bytes of data: 
   Reply from192.168.10.1: bytes=32 time<10ms TTL=247 
   Reply from192.168.10.1: bytes=32 time=10ms TTL=247 
   Reply from192.168.10.1: bytes=32 time<10ms TTL=247 
   Reply from192.168.10.1: bytes=32 time<10ms TTL=247 
   Ping statistics for 192.168.10.1: 
   Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), 
   Approximate round trip times in milli-seconds: 
   Minimum = 0ms, Maximum = 10ms, Average = 2ms
   

2. Type show running-config and press Enter to look for the SNMP information. In the sample output, "public" is the read-only community string and "private" is the read-write community string.

   Router#show running-config
   Building configuration...
   Current configuration : 2937 bytes!
   version 12.4
   service timestamps debug datetime msec
   service timestamps log datetime msec
   snmp-server community public RO
   snmp-server community private RW
   !--- Output is suppressed for brevity.
   

3. Alternatively, type show snmp command in the enable mode. If you see this message, it also indicates that SNMP has not been enabled on the router.

   Router#show snmp
   %SNMP agent not enabled 
   Router#
   

Modify SNMP Community Strings

To modify the current Read-only (RO) and Read-write (RW) community string, first you need to delete these community strings already configured in the router.

Follow these steps to modify SNMP community strings:

1. Type show running-config and press Enter to look for the SNMP information. In the sample output, "public" is the read-only community string and "private" is the read-write community string.

   Router#show running-config
   Building configuration...
   Current configuration : 2937 bytes!
   version 12.4
   service timestamps debug datetime msec
   service timestamps log datetime msec
   snmp-server community public RO 
   snmp-server community private RW
   !--- Output is suppressed for brevity.
   

2. Type configure terminal and press Enter to enter the router configuration mode.

   Router#configure terminal
   Router(config)#
   

3. Type no snmp-server community XXXX RO and press Enter to delete the Read-only (RO) community string where "XXXX" is the Read-only community string.

   Router(config)#no snmp-server community XXXX RO
   

4. Type no snmp-server community YYYY RW and press Enter to delete the Read-write (RW) community string where "XXXX" is the Read-write community string.

   Router(config)#no snmp-server community YYYY RW
   

5. Enter the new RO community strings. Type snmp-server community XXXX RO and press Enter where "XXXX" is the Read-only community string.

   Router(config)#snmp-server community XXXX RO
   

6. Enter the new RW community strings. Type snmp-server community YYYY RW and press Enter where "XXXX" is the Read-write community string.

   Router(config)#snmp-server community YYYY RW
   

7. Type exit and press Enter.

   Router(config)#exit
   Router#
   

8. Type write memory and press Enter.

   Router#write memory
   

   Note: To disable the SNMP Community strings follow steps 3 and 4 of the section Modify SNMP Community Strings.

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Next Step

You have completed the procedure to configure community strings on your Cisco router. To make further changes to your router, refer to the Routers Support Page.

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Troubleshoot the Procedure

This section provides information about common problems that you may encounter. If this information does not solve your problem, contact the SMB Technical Assistance Center (SMB TAC) for assistance.

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Related Information

• Configure an IP Address on Your PC
• Cable Descriptions
• Create a HyperTerminal Connection
• Set Up Internet Security on a Cisco Router