|  | 1 | = SNMP Hands - On = | 
          
            |  | 2 |  | 
          
            |  | 3 | === Goals === | 
          
            |  | 4 | - Install and learn to use the SNMP commands | 
          
            |  | 5 | - Install vendor specific MIBs and use those with the SNMP commands | 
          
            |  | 6 |  | 
          
            |  | 7 | === Notes === | 
          
            |  | 8 | - For below hands-on we will be using Ubuntu 20.04 version. | 
          
            |  | 9 | - If you are installing snmp client (manager) tools on a remote server/computer you will need to connect the server through a SSH connection. | 
          
            |  | 10 |  | 
          
            |  | 11 | == Installing SNMP Client (Manager) tools == | 
          
            |  | 12 |  | 
          
            |  | 13 | Connect to the server which will be used as the NMS (Network Management Station) and Open the Terminal program. | 
          
            |  | 14 |  | 
          
            |  | 15 | Update your software package repository | 
          
            |  | 16 | {{{ | 
          
            |  | 17 | $ sudo apt-get update | 
          
            |  | 18 | }}} | 
          
            |  | 19 | This might take a few moments if everyone in class is doing this at the same moment. | 
          
            |  | 20 |  | 
          
            |  | 21 | Install the net-snmp tools: | 
          
            |  | 22 | {{{ | 
          
            |  | 23 | $ sudo apt-get install snmp | 
          
            |  | 24 | $ sudo apt-get install snmp-mibs-downloader | 
          
            |  | 25 | }}} | 
          
            |  | 26 | The second of the two commands downloads the standard IETF and IANA SNMP MIBs which are not included by default. | 
          
            |  | 27 |  | 
          
            |  | 28 | Now, edit the file /etc/snmp/snmp.conf: | 
          
            |  | 29 | {{{ | 
          
            |  | 30 | $ sudo vi /etc/snmp/snmp.conf | 
          
            |  | 31 | }}} | 
          
            |  | 32 |  | 
          
            |  | 33 | Note: Here we are using '''vi''' editor. You can use any text editor you are familiar with | 
          
            |  | 34 |  | 
          
            |  | 35 | Change this line: | 
          
            |  | 36 | {{{ | 
          
            |  | 37 | mibs : | 
          
            |  | 38 | }}} | 
          
            |  | 39 |  | 
          
            |  | 40 | so that it looks like: | 
          
            |  | 41 | {{{ | 
          
            |  | 42 | # mibs : | 
          
            |  | 43 | }}} | 
          
            |  | 44 |  | 
          
            |  | 45 | (You are "commenting out" the empty mibs statement, which was telling the snmp* tools not to automatically load the mibs in the /usr/share/mibs/ directory) | 
          
            |  | 46 |  | 
          
            |  | 47 | === User specific SNMP configurations === | 
          
            |  | 48 | Now, in your home directory make a .snmp directory with file snmp.conf inside it, make it readable only be you, and add the credentials to it: | 
          
            |  | 49 | {{{ | 
          
            |  | 50 | $ cd | 
          
            |  | 51 | $ mkdir .snmp | 
          
            |  | 52 | $ chmod 700 .snmp/ | 
          
            |  | 53 | $ vi .snmp/snmp.conf | 
          
            |  | 54 | }}} | 
          
            |  | 55 |  | 
          
            |  | 56 |  | 
          
            |  | 57 | Put the following contents in the file: | 
          
            |  | 58 | {{{ | 
          
            |  | 59 |  | 
          
            |  | 60 | defVersion 3 | 
          
            |  | 61 |  | 
          
            |  | 62 | # SNMP v3 Configurations | 
          
            |  | 63 | defSecurityLevel authNoPriv | 
          
            |  | 64 | defSecurityName admin | 
          
            |  | 65 | defAuthPassphrase <class passowrd> | 
          
            |  | 66 | defAuthType SHA | 
          
            |  | 67 |  | 
          
            |  | 68 | # SNMP v2c default community string | 
          
            |  | 69 | defCommunity <class passowrd> | 
          
            |  | 70 |  | 
          
            |  | 71 | }}} | 
          
            |  | 72 |  | 
          
            |  | 73 | == Configuration of SNMP Agent on Routers and Switches == | 
          
            |  | 74 |  | 
          
            |  | 75 | ==== Cisco ==== | 
          
            |  | 76 |  | 
          
            |  | 77 | connect to your router and go to configure mode. | 
          
            |  | 78 | {{{ | 
          
            |  | 79 | Router> enable | 
          
            |  | 80 |  | 
          
            |  | 81 | Router# configure terminal | 
          
            |  | 82 | }}} | 
          
            |  | 83 | Now we need to add an Access Control List rule for SNMP access, turn on SNMP, assign a read-only SNMP community string as well as a SNMPv3 group and user and tell the router to maintain SNMP information across reboots. To do this we do: | 
          
            |  | 84 | {{{ | 
          
            |  | 85 | Router(config)# access-list 99 permit 192.248.6.0 255.255.255.0 | 
          
            |  | 86 | Router(config)# snmp-server community <class passowrd> ro 99 | 
          
            |  | 87 | Router(config)# snmp-server group ReadGroup v3 auth access 99 | 
          
            |  | 88 | Router(config)# snmp-server user admin ReadGroup v3 auth sha <Class Password> | 
          
            |  | 89 | Router(config)# snmp-server ifindex persist | 
          
            |  | 90 | Now let's exit and save this new configuration to the routers permanent config. | 
          
            |  | 91 |  | 
          
            |  | 92 | Router(config)# exit | 
          
            |  | 93 | Router# write memory | 
          
            |  | 94 | Router# exit | 
          
            |  | 95 | }}} | 
          
            |  | 96 |  | 
          
            |  | 97 | ==== HP ==== | 
          
            |  | 98 | Connect to the Router and go to config mode | 
          
            |  | 99 | {{{ | 
          
            |  | 100 | <Router> system-view | 
          
            |  | 101 | }}} | 
          
            |  | 102 |  | 
          
            |  | 103 | Add the following configurations | 
          
            |  | 104 | {{{ | 
          
            |  | 105 | [Router]acl number 2000 | 
          
            |  | 106 | [Router-acl-basic-2000]rule 0 permit source 192.248.6.0 0.0.0.255 | 
          
            |  | 107 | [Router]snmp-agent | 
          
            |  | 108 | [Router]snmp-agent community read <class passowrd> | 
          
            |  | 109 | [Router]snmp-agent sys-info version all | 
          
            |  | 110 | [Router]snmp-agent group v3 ReadGroup authentication acl 2000 | 
          
            |  | 111 | [Router]snmp-agent usm-user v3 admin ReadGroup authentication-mode sha <class passowrd> | 
          
            |  | 112 | }}} | 
          
            |  | 113 |  | 
          
            |  | 114 | == Testing SNMP == | 
          
            |  | 115 | Now we have both a SNMP Manager and SNMP Agent. To check that your SNMP installation works, run the snmpstatus command on the SNMP Manager host. | 
          
            |  | 116 |  | 
          
            |  | 117 | {{{ | 
          
            |  | 118 | $ snmpstatus <IP_ADDRESS> | 
          
            |  | 119 | }}} | 
          
            |  | 120 | Note that you just used was the SNMPv3 because we set the default version as SNMPv3. Try again, adding "-v2c" as a parameter. Notice that the command automatically uses the community string in the snmp.conf file instead of the v3 user credentials. Try "-v1". | 
          
            |  | 121 |  | 
          
            |  | 122 | To use the SNMP v2 or v1 we can add an option as below. Which will override the settings in the configuration file(/.snmp/snmp.conf). | 
          
            |  | 123 |  | 
          
            |  | 124 | snmpstatus -v2c <IP_ADDRESS> | 
          
            |  | 125 | snmpstatus -v1 <IP_ADDRESS> | 
          
            |  | 126 |  | 
          
            |  | 127 | Again we didn't want set Community string as it was set in the manager configuration file. | 
          
            |  | 128 |  | 
          
            |  | 129 | For the Router, | 
          
            |  | 130 | {{{ | 
          
            |  | 131 | #snmpstatus <Router IP> | 
          
            |  | 132 | }}} | 
          
            |  | 133 |  | 
          
            |  | 134 | For the Switch, | 
          
            |  | 135 | {{{ | 
          
            |  | 136 | #snmpstatus <Switch IP> | 
          
            |  | 137 | }}} |