There are databases where objects are stored. MIB acts as a translator and allows an SNMP server to query an object using a textual OID instead of numeric. For example, to retrieve a device name through SNMP queries, we can use the OID 1.3.6.1.2.1.1.5.0 or the OID SNMPv2-MIB::sysName.0. Both of them will give you the exact same result. But the textual OID is easier to understand than just a numeric OID. We can compare MIB to OID as being similar to a domain name to an IP address. Some manufacturers provide their own MIB since they do not exist in the standard MIB. It is important to know the MIBs when configuring unsupported devices for monitoring tools. There are a number of MIBs ready to be downloaded. Proxmox does not install any MIB by default. It has to be manually installed.

There are three versions of SNMP currently available. Before implementing an SNMP infrastructure, it is important to know which version to use. The three versions are as follows:

• SNMP version 1: This is the oldest SNMP version, which only supports 32-bit counters and has no security at all. A community string is sent as plain text in this SNMP.
• SNMP version 2: This has all the features of version 1, with added features to support 64-bit counters. Most of the devices nowadays support version 2.
• SNMP version 3: This has all the features of version 1 and 2, with the added benefits of security. Both encryption and authentication are added to counters. If security is the biggest concern, this is the SNMP version that should be used.

SNMP is not installed by default in Proxmox. The following steps show how to install SNMP in Proxmox and how to configure it.

Run the following command to install SNMP on Proxmox nodes:

# apt-get install snmpd snmp

Add the following repository in the /etc/apt/sources.list of the Proxmox node. This is used to add a repository to install SNMP MIBs:

deb http://http.us.debian.org/debian/stretch main non-free

Run the following commands to install SNMP MIBs:

# apt-get update
# apt-get install snmp-mibs-downloader

Open the SNMP /etc/snmp/snmpd.conf configuration file using an editor.

Ensure that the following line is uncommented. We can specify the node IP address. SNMP listens on port 161. Change it here if required:

agentAddress udp:127.0.0.1:161

Add the following line to the SNMP configuration file:

rocommunity <secret_string> <IP/CIDR>

In our example, we have added the following line:

rocommunity SecretSNMP 172.16.0.0/24

Save the file and restart SNMP using the following command:

#service snmpd restart