How To Install and Configure SNMP on RHEL 7 or CentOS 7
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The document provides instructions on how to install and configure SNMP on RHEL 7. It describes downloading the required packages, editing the configuration file, opening the required port in the firewall, and testing SNMP queries locally and remotely. SNMP can be used to monitor devices and retrieve statistics on parameters like performance, usage, and storage. The three main versions of SNMP are also outlined, highlighting their features around security, querying, and remote configuration capabilities.
How To Install and Configure SNMP on RHEL 7 or CentOS 7
- 1. How To Install and Configure SNMP on RHEL 7 i | P a g e Table of Contents Overview.......................................................................................................................................................1 Applies To......................................................................................................................................................1 Pre-Requisites ...............................................................................................................................................1 Installation and Configuration procedure.....................................................................................................1 Check Package...........................................................................................................................................1 Install Package...........................................................................................................................................1 Verify Installation......................................................................................................................................2 SNMP – Configuration File........................................................................................................................2 Default Configuration File – Snippet.....................................................................................................2 Firewall Configuration...................................................................................................................................3 Firewall Configuration – Open UDP Port ..................................................................................................3 Firewall Configuration – Reload................................................................................................................3 Firewall Configuration – List .....................................................................................................................3 snmpwalk – localhost Query.....................................................................................................................4 snmpwalk – Remote Query.......................................................................................................................4 SNMP Configuration .....................................................................................................................................5 Listening address ......................................................................................................................................5 SNMP Daemon Management .......................................................................................................................5 Troubleshooting............................................................................................................................................6 Timeout: No Response from 127.0.0.1.....................................................................................................6 Error Message.......................................................................................................................................6 Cause.....................................................................................................................................................6 Resolution .............................................................................................................................................6 SNMP Version Features ................................................................................................................................7
- 2. How To Install and Configure SNMP on RHEL 7 1 | P a g e Overview SNMP stands for “Simple Network Management Protocol”, it can be utilized to monitor any devices that support snmp, few of the devices are server, router, network printers, firewalls. SNMP can monitor a variety of parameters for these devices such as server performance, network usage, disk utilization. Applies To Tested on RHEL 7, CentOS 7, though it can be configured on most of the *nix flavor of OS. Pre-Requisites snmp, snmp-utils Installation and Configuration procedure First of all, we will check if the package is already installed else we will install the packages. Check Package Check if the package is already installed, to check package installation status, run the command; rpm -qa | grep net-snmp net-snmp-utils Install Package After checking the package installation status, if the package is not installed. Install the package to install run the command; yum install net-snmp net-snmp-utils -y
- 3. How To Install and Configure SNMP on RHEL 7 2 | P a g e Verify Installation After installing the net-snmp packages verify if the package is installed, to check package installation status, run the command; rpm -qa | grep net-snmp* SNMP – Configuration File Default configuration file that is configured as per the below. To display current configuration without comments and lines non-blank lines, run command; grep -v "^$" /etc/snmp/snmpd.conf | grep -v '^ *#' Default Configuration File – Snippet com2sec notConfigUser default public group notConfigGroup v1 notConfigUser group notConfigGroup v2c notConfigUser view systemview included .1.3.6.1.2.1.1 view systemview included .1.3.6.1.2.1.25.1.1 access notConfigGroup "" any noauth exact systemview none none syslocation Unknown (edit /etc/snmp/snmpd.conf) syscontact Root <root@localhost> (configure /etc/snmp/snmp.local.conf) dontLogTCPWrappersConnects yes
- 4. How To Install and Configure SNMP on RHEL 7 3 | P a g e Firewall Configuration SNMP protocol works on UDP port “161” and this port needs to be opened in order to listen and scan the report from remote servers and for latest version of snmp service supports running on TCP port which is again on “161”. Firewall Configuration – Open UDP Port After installing and checking the default configuration, the next step that needs to be done is to open firewall port, snmp protocol run on UDP port 161. firewall-cmd --permanent --add-port=161/udp Firewall Configuration – Reload Reload the firewall configuration. firewall-cmd --reload Firewall Configuration – List After reloading firewall daemon, list the current rules set. firewall-cmd --list-all
- 5. How To Install and Configure SNMP on RHEL 7 4 | P a g e snmpwalk – localhost Query After configuring the firewall, you can go ahead and test the snmp query data on the localhost it should be able to retrieve the OID values when you run. To retrieve the information run the command; snmpwalk -v 1 -c public -O e 127.0.0.1 snmpwalk – Remote Query To query from a remote client to retrieve the OID values when you run. To retrieve the information run the command; in this case we are querying from a windows machine. snmpwalk -r:54.165.245.172 -q -c:public
- 6. How To Install and Configure SNMP on RHEL 7 5 | P a g e SNMP Configuration In order to SNMP to work for any query requests, it should be configured only agentaddress directives is listed and configured, similarly other directives can be configured according to the business needs. Listening address This attribute will associate the IP address wherein the snmp service will listen on. Attribute Name IP Address Information Port agentaddress 127.0.0.1 161 agentaddress IP Address 161 agentaddress 127.0.0.1:161 SNMP Daemon Management State Command Purpose Enable systemctl enable snmpd Enable the service to start at boot and start automatically Start systemctl start snmpd Start the service Stop systemctl stop snmpd Stop the service Restart systemctl restart snmpd Restart the service Disable systemctl disable snmpd Disable the service to start at upon booting Mask systemctl mask snmpd Masking the service to disable dynamic and manual starting.
- 7. How To Install and Configure SNMP on RHEL 7 6 | P a g e Troubleshooting Timeout: No Response from 127.0.0.1 Error Message Timeout: No Response from 127.0.0.1 Cause One of the cause is the service is not running, start the service. Another cause is when the remote server doesn’t have port is blocked or not listening default port on the client. systemctl status snmpd Resolution To resolve the issue we will start the daemon and query again for the first cause, for the second cause ensure firewall port is configured such that UDP port 161 is opened and listening, check firewall configuration section. systemctl start snmpd
- 8. How To Install and Configure SNMP on RHEL 7 7 | P a g e SNMP Version Features SNMP has 3 versions currently, that can be configured based on the business needs. The below table will give insight into different versions and its features that provide device statistics. SNMP Version Features Version 1 This provides device statistics and error reporting without consuming a lot of system resources. Security was limited to community strings and access controls based on the IP address of the querying server. Data communication wasn't encrypted. Version 2 This is referred to as v2c which expanded the number of supported error codes, increased the size of counters used to track data, and has the ability to do bulk queries that more efficiently loaded response packets with data Version 3 This version provides greater security and remote configuration capabilities than earlier versions. Access is not only limited to a single community string for read-only and read/write access, as usernames and passwords can also be configured in this version. Support for encrypted SNMP data transfer and transfer error detection is also provided.