SNMP walk

An SNMP walk is a method used to retrieve multiple pieces of information from a networked device using the SNMP - Simple Network Management Protocol. It's essentially a series of SNMP GETNEXT requests issued sequentially, enabling an administrator or network tool to gather a large amount of data from a device, especially when the exact points of data (or OIDs) aren't known beforehand.

This method starts by querying a device for an OID value. Once that value is returned, the system will ask for the next value in sequence. This continues until there are no more values to return within that branch of the MIB tree. The result is a comprehensive list of all available OIDs and their values for that device.

Use Cases: Administrators might use SNMP walk to:

  • Debug or troubleshoot issues.
  • Discover what information is available on a device.
  • Backup or archive the current state/configuration of a device.
  • Monitor device health and performance.

Tools: There are many network monitoring tools and utilities that can perform SNMP walks. One popular command-line tool for this purpose is snmpwalk, which is part of the NET-SNMP suite.

When using the snmpwalk tool, a command might look something like this:

snmpwalk -v2c -c public 192.168.1.1

Where:

  • -v2c indicates SNMP version 2c.
  • -c public specifies the community string (akin to a password for SNMP access); "public" is the default read-only community string for many devices, though it's recommended to change it in a real-world scenario for security reasons.
  • 192.168.1.1 is the IP address of the target device.

This command would retrieve the values of all the OIDs on the device with IP address 192.168.1.1 using the SNMP v2c protocol.

http://www.net-snmp.org/