SNMP
Diagnosing SNMP credential, connectivity, and version issues when SNMP data isn't appearing.
Symptoms: Discovery completes, SNMP port (161) detected on hosts, but no SNMP data (sysName, interfaces, LLDP neighbors) appears.
Check credential assignment
Creating a credential alone doesn't activate SNMP. It must be assigned to the network or to specific hosts.
How to verify: Go to Assets > Networks → select the network → check that an SNMP credential is set. Or hover the Network chip on Discover > Daemons to see the credential assignment.
See the SNMP Credentials guide for setup steps.
Verify device responds to SNMPv2c
From the daemon host, test SNMP connectivity directly:
# Try the default community string
snmpwalk -v2c -c public DEVICE_IP 1.3.6.1.2.1.2.2.1.2
# Try your configured community string
snmpwalk -v2c -c YOUR_COMMUNITY_STRING DEVICE_IP 1.3.6.1.2.1.2.2.1.2- If
publicworks but your custom string doesn't → credential mismatch - If neither works → SNMP is not enabled on the device or it doesn't support SNMPv2c
Check SNMP version compatibility
Scanopy supports SNMPv2c only. If devices enforce SNMPv3-only, SNMP queries will fail silently. SNMPv3 support is on the roadmap.
Check daemon logs
Enable debug logging and look for these messages during a scan of the target host:
| Log message | Meaning |
|---|---|
Creating SNMPv2c session | Daemon is attempting SNMP |
SNMP session created successfully | UDP socket opened |
SNMP GET {name} failed from {ip} | OID query failed (auth or protocol error) |
SNMP GET {name} timeout from {ip} | Device didn't respond within 5s |
SNMP system info retrieved with sys_descr/sys_name | Success |
No working SNMP credential found for {ip} | All credentials tried, none worked |
Check host SNMP data
Open the host edit modal to inspect what SNMP has collected:
- SNMP tab — shows sys_descr, sys_name, sys_location, sys_contact, and credential assignment
- ifEntry tab — shows the interface table from the SNMP walk
If both tabs are empty after a scan with credentials assigned, work through the checks above.