ACNet

Read-only SNMP

SNMP reads management information from devices you administer. It is off by default. Ordinary scans never send SNMP.

Updated 5 October 2026

Where to configure it

Settings › SNMP profiles › Add profile. This is not a network profile.

Set a name, the hosts or ranges that may be asked, the UDP port (161 unless you change it), the version and the credentials.

Test sends one read request to one address of the profile.

On Devices, choose the profile under Scan options. It applies to that scan only and stays chosen until you change it. Only addresses inside the scanned network are contacted.

ACNetGet onlyAgentvaluesKeychainnot in exports
Illustrative example. Not a map of a physical network and not a live capture.

Versions

SNMPv3 with SHA-256 authentication and AES-128 encryption is the recommended choice in the app. SHA-512 is also offered. SHA-1 is offered only for older agents.

SNMPv2c sends the community string and every answer unencrypted. Anyone on the network can read them. Use it only for devices without SNMPv3.

  1. On the device, create a read-only user or community. Do not put a real password in a screenshot or a support message.
  2. In ACNet, enter that read-only account. ACNet only sends Get, GetNext and GetBulk. It never changes a setting.
  3. Credentials are stored in this device’s Keychain. They are not stored in network profiles, history, exports or logs, and they are removed with the SNMP profile.

What the result means

You see system name, description, model and serial number, and interfaces. Switch tables (which device is on which port) are off by default because large switches take longer to read. Many home routers have no agent. Managed switches, printers, NAS and servers often do.

Profile targets are IPv4 addresses or IPv4 networks in CIDR notation. A scan asks at most 64 agents, and only an address that is both in this profile and inside the network being scanned. Monitoring rules do not use SNMP. SNMPv3 passwords need at least 8 characters. Encryption is AES-128-CFB and stays on unless you switch it off; without it, answers travel readable on the network. DES, AES-192, AES-256, MD5 and SNMPv1 are not implemented. Credentials stay in the Keychain on this device, are not synced, and can be read only while the device is unlocked.

Troubleshooting

No answer: the agent is off, listens on another port, filters this address, the community is wrong, or the host is outside the profile ranges.

Authentication failed: the password or authentication protocol does not match.

Could not decrypt: the privacy password does not match.

Outside its time window: the agent clock and engine time disagree. Test again.

Security level not supported or access refused: the user on the device is bound to another level or view.