- \n
- SNMP is a S<\/strong>imple N<\/strong>etwork M<\/strong>anagement P<\/strong>rotocol,<\/strong>\u00a0which is a simple set of operations (and the information these operations gather) that gives administrators the ability to change the state of some SNMP based device.<\/li>\n
- The device can be a router, switch, printers, storage devices, Unix systems, Windows systems, power supplies, etc.<\/li>\n<\/ul>\n
What is snmpwalk?<\/h3>\n
- \n
- snmpwalk command facilitates the GETNEXT procedure for us.<\/li>\n
- SNMP GETNEXT\u00a0request to query for information on a network entity, the information could be of sysDescr or sysLocation, etc.<\/span><\/li>\n
- Therefore snmpwalk is nothing but SNMP GETNEXT requests to query a network device for information until end of MIB is reached.<\/li>\n<\/ul>\n
\nWe will do the following in this post:<\/p>\n
1. Enable SNMP configuration on the device
\n2. Create device templates
\n2.i. Using snmprec.py
\n2.ii. From .snmpwalk file
\n3. Run simulated SNMP device for the generated device template<\/p>\n<\/p>\n
1. Enable SNMP configuration on the device<\/h4>\n
We need to enable SNMP config on the device that you would like to simulate by creating a device template for it. Follow the instructions to achieve it.<\/p>\n
a) To enable SNMP configuration on the device we need to install snmp and snmpd.<\/p>\n
sudo apt-get update\r\nsudo apt-get install snmp snmpd\r\n<\/pre>\n
b) Update snmpd.conf file
\nPlease note snmpd.conf file will be in\/etc\/snmp\/snmpd.conf<\/code><\/p>\nc) Open the daemon\u2019s configuration file with sudo privileges<\/p>\n
sudo vim snmpd.conf\r\necho agentAddress udp:127.0.0.1:161 >>\/etc\/snmp\/snmpd.conf<\/pre>\n
save the file.<\/p>\n
d) Restart the snmpd service<\/p>\n
sudo service snmpd restart<\/pre>\n
e) Check if it’s working<\/p>\n
snmpwalk -v2c -c public localhost<\/pre>\n
Note: here v2c refers to SNMP version 2, -c refers to the community string.<\/span><\/p>\n
![\"snmpwalk](\"https:\/\/qxf2.com\/blog\/wp-content\/uploads\/2020\/05\/snmpwalk-300x184.jpg\")
<\/a><\/p>\n
\n2. Create device templates<\/h3>\n
Next, we will create device templates which requires installing snmpsim module and then create snmprec files using either Using snmprec.py or a .snmpwalk file.<\/p>\n
a) Install snmpsim python module using
pip<\/code><\/p>\npip install snmpsim<\/pre>\n
b) There are two ways to create device templates.<\/p>\n
- <\/ul>\n
i. Using snmprec.py<\/h4>\n
Here we will generate snmprec file by using snmprec.py<\/strong> tool of snmpsim python module and store the response data in a output snmprec file.<\/p>\n
snmprec.py --agent-udpv4-endpoint=127.0.0.1 --output-file=.\/local.snmprec<\/pre>\n
Note:-Execute the above command from your \/home\/ubuntu repository,\u00a0 otherwise it would give out\u00a0permission denied error.<\/span><\/p>\n
![\"Recording](\"https:\/\/qxf2.com\/blog\/wp-content\/uploads\/2020\/05\/snmprec-300x39.jpg\")
<\/a><\/p>\nAfter using the tool, a new\u00a0.snmprec file will be generated, depending upon the output file name given.<\/p>\n
![\"snmprec](\"https:\/\/qxf2.com\/blog\/wp-content\/uploads\/2020\/05\/local-300x186.jpg\")
<\/a><\/p>\n
\nii. From .snmpwalk file<\/h4>\n
Here we will generate .snmpwalk file and then convert that into a .snmprec file by using datafile.py<\/strong> tool of snmpsim Python module.<\/p>\n
To save the snmpwalk snapshot in a file use the below command<\/p>\n
snmpwalk -v2c -c public -ObentU localhost 1.3.6 >>localhost.snmpwalk<\/pre>\n
After this, a “localhost.snmpwalk<\/strong>” file will be generated which will contain the snmpwalk snapshot of the localhost. Next step is to convert the .snmpwalk<\/strong> file to .snmprec<\/strong> file by using datafile.py<\/strong> tool.<\/p>\n
datafile.py --input-file=.\/localhost.snmpwalk --source-record-type=snmpwalk --output-file=.\/localhost.snmprec<\/pre>\n
Note:-Execute the above command from your \/home\/ubuntu repository,\u00a0 otherwise it would give out a\u00a0permission denied error.<\/span><\/p>\n
![\"conversion](\"https:\/\/qxf2.com\/blog\/wp-content\/uploads\/2020\/05\/datafile.py_-300x100.jpg\")
<\/a><\/p>\n
\n3. Run simulated SNMP device for the generated device template<\/h4>\n
To check if our device template is working or not, let’s do a test run.<\/p>\n
a) We will use SNMP Version 3<\/p>\n
snmpsimd.py --v3-engine-id=010203040505060880 --v3-user=qxf2 --data-dir=\/home\/ubuntu\/data --agent-udpv4-endpoint=127.0.0.1:6464 &<\/pre>\n
![\"snmpsimd.py](\"https:\/\/qxf2.com\/blog\/wp-content\/uploads\/2020\/05\/snmpv3-300x68.jpg\")
<\/a><\/p>\nb) Let us see if the simulated device is responding.<\/p>\n
snmpwalk -v2c -c localhost 127.0.0.1:6464<\/pre>\n
Note:\u00a0-c localhost<\/strong> is the community string &\u00a0v2c<\/strong> is the SNMP version 2
\n![\"snmpwalk](\"https:\/\/qxf2.com\/blog\/wp-content\/uploads\/2020\/05\/snmpwalk1-300x106.jpg\")
<\/a><\/p>\n
\nI hope this blog helps you create hardware device templates for your testing purposes.<\/p>\n
For reference and more details on creating device templates:-
\nBuilding simulation data<\/a><\/p>\n - Therefore snmpwalk is nothing but SNMP GETNEXT requests to query a network device for information until end of MIB is reached.<\/li>\n<\/ul>\n
- The device can be a router, switch, printers, storage devices, Unix systems, Windows systems, power supplies, etc.<\/li>\n<\/ul>\n
![\"snmpwalk](\"https:\/\/qxf2.com\/blog\/wp-content\/uploads\/2020\/05\/snmpwalk.jpg\")
<\/a><\/p>\n