What Is snmpwalk? Command Usage, Examples, and Troubleshooting
SNMP and SNMPWALK are related, but they are not the same thing. What is snmpwalk? snmpwalk is a Net-SNMP command-line tool that sequentially queries all values beneath a specific OID on an SNMP agent. It is a cornerstone for device discovery, monitoring deployment, and troubleshooting processes.
snmpwalk is a Net-SNMP command-line utility that sequentially queries all values starting from a specified OID on an SNMP agent. Unlike snmpget, which reads a single value, snmpwalk lists multi-row data such as a device's interfaces, hardware inventory, disk, and memory status in a single command. It is the go-to tool for network device discovery, monitoring setup, and SNMP troubleshooting.
What is SNMP? The Importance of SNMP in Network Monitoring
How Does snmpwalk Work?
snmpwalk takes a starting OID and repeatedly asks the agent, "What is the next value after this?" As the agent returns the next object in the OID tree, the command continues until it reaches the end of the specified subtree. From a user perspective, this looks like walking through a tree structure.
- SNMP v1: Uses a GETNEXT request at each step; each request returns a single value.
- SNMP v2c and v3: Net-SNMP uses GETBULK by default. Because multiple values are retrieved in a single request, large tables are traversed much faster.
If no OID is provided, snmpwalk starts from the agent's default starting point (usually .1.3.6.1.2.1, which is MIB-2). On a large device, this can generate thousands of lines, so a target OID is usually specified in the field.
Installation
snmpwalk is not a standalone program; it is part of the Net-SNMP package.
# Debian / Ubuntu
sudo apt install snmp
# RHEL / Rocky / AlmaLinux
sudo dnf install net-snmp-utils
# macOS (Homebrew)
brew install net-snmpOn Windows, you can install the Net-SNMP Windows package or use the Linux version via WSL. After installation, verify the version with the following command:
snmpwalk -VTip: On Debian-based systems, default installations may not include MIB files, resulting in numeric OIDs instead of names in the output. To enable name resolution, install the corresponding MIB package or specify the MIB directory using -m ALL -M +/path/to/mibs parameters.
Basic Syntax and Parameters
snmpwalk [options] target_device [OID]| Parameter | Description |
|---|---|
-v 1 | 2c | 3 |
SNMP version |
-c community |
Community string (v1 and v2c) |
-l level |
v3 security level: noAuthNoPriv, authNoPriv, authPriv |
-u user |
v3 username |
-a / -A |
v3 authentication protocol (e.g., SHA) and password |
-x / -X |
v3 encryption protocol (e.g., AES) and password |
-On |
Show OIDs numerically instead of names |
-Oq / -Ov |
Quiet output / values only |
-t / -r |
Timeout (seconds) / retry count |
-Cc |
Disable checking whether OIDs are increasing |
-Cr N |
Max-repetitions value for GETBULK |
-m ALL |
Load all MIB modules |
Practical Examples (v2c and v3)
-
General Info
Reading general device info (system group):
snmpwalk -v2c -c public 192.168.1.1 system
Returns basic fields such as device name, description, uptime, and contact information. -
Numeric OID
Querying with a numeric OID:
snmpwalk -v2c -c public -On 192.168.1.1 .1.3.6.1.2.1.1 -
Interface List
Listing interface names:
snmpwalk -v2c -c public 192.168.1.1 ifDescr -
Traffic Counters
Interface traffic counters (64-bit):
snmpwalk -v2c -c public 192.168.1.1 ifHCInOctets -
SNMP v3
Secure query with SNMP v3:
snmpwalk -v3 -l authPriv -u monitoring_user -a SHA -A "auth_pass" -x AES -X "priv_pass" 192.168.1.1 system
Most Commonly Used OIDs
| Information | MIB Object | OID |
|---|---|---|
| Device description | sysDescr | .1.3.6.1.2.1.1.1 |
| Uptime | sysUpTime | .1.3.6.1.2.1.1.3 |
| Device name | sysName | .1.3.6.1.2.1.1.5 |
| Interface table | ifTable | .1.3.6.1.2.1.2.2 |
| Extended interface (64-bit) | ifXTable | .1.3.6.1.2.1.31.1.1 |
| Disk / memory | hrStorageTable | .1.3.6.1.2.1.25.2.3 |
| Physical hardware inventory | entPhysicalTable | .1.3.6.1.2.1.47.1.1.1 |
How to Read the Output?
IF-MIB::ifDescr.1 = STRING: GigabitEthernet0/1
IF-MIB::ifDescr.2 = STRING: GigabitEthernet0/2
IF-MIB::ifOperStatus.1 = INTEGER: up(1)- IF-MIB::ifDescr: The MIB and object name to which the item belongs.
- .1, .2: Index. Represents each row in tables; think of it as the interface number.
- STRING / INTEGER: Data type of the value. Other common types:
Counter32,Counter64,Gauge32,Timeticks.
Common Errors and Solutions
-Cc parameter.Frequently Asked Questions
Q: What is snmpwalk used for?
snmpwalk sequentially queries all values starting from a specified OID on an SNMP agent. It is used to quickly list device interfaces, hardware info, resource usage, and uptime with a single command.
Q: What is the difference between snmpwalk and snmpget?
snmpget returns the value of a single OID. snmpwalk traverses the entire subtree under the given OID and lists multiple values together.
Q: Which port does snmpwalk use?
snmpwalk sends queries to the target device's UDP port 161. Access to this port must be open through the firewall.
Q: Why does snmpwalk throw a 'Timeout: No Response from host' error?
The most common reasons are an incorrect community string or SNMP v3 user info, blocked UDP 161 access, a disabled SNMP service on the device, or the querying IP not being on the device's permit list.
Automate Your Network Monitoring and SNMP Processes
Move beyond manual command-line queries and contact our experts to centrally and continuously monitor your entire network infrastructure.
Contact Us →