User Guide — FlowMoSNMP

1. Getting Started

When you launch FlowMoSNMP for the first time, the onboarding window appears. Fill in your device details to start monitoring.

What you need

The IP address or hostname of an SNMP-enabled device (router, switch, NAS, etc.)
The SNMP community string (usually public for v1/v2c) or SNMPv3 credentials
The interface index you want to monitor (the onboarding window can discover this for you)

Onboarding steps

Enter your Device IP / Host and Community String
Choose your SNMP Version (v1, v2c, or v3)
Tap Discover... next to Interface Index to browse available interfaces on the device
Tap Test to verify connectivity — a green checkmark and the device name confirm success
Tap Get Started to begin monitoring

Tip: If you have FlowMoSNMP installed on another Mac with iCloud Sync enabled, the onboarding window will detect your existing settings and offer to import them automatically.

2. Menu Bar

FlowMoSNMP lives entirely in the macOS menu bar — there is no Dock icon and no main window. Once connected, the menu bar shows your current bandwidth rates.

Display modes

Stacked (default) — upload rate on top, download below, two lines
Inline — both rates side by side on a single line
Out only — shows only the upload rate
In only — shows only the download rate

You can change the display mode in Settings → Display → Show Rates. The menu bar width adapts automatically to the rate tier being displayed — lower rates (KB/s, Kbps) use less space than higher tiers (MB/s, Mbps), and bytes suffixes are slightly narrower than bits. The width only shifts when crossing a tier boundary, not on every poll.

Interactions

Left-click — opens or closes the dashboard popover
Right-click — opens the context menu with access to Settings, Connection Log, SNMP Data, Copy Stats, About, and Quit

Error state

When the app cannot reach your device, the menu bar text changes color (default: orange) so you can see at a glance that something is wrong. The color returns to normal when connectivity is restored. Both the normal and error colors are customizable in Settings → System. After an outage, the first successful poll starts fresh — there is no artificial spike from stale counter values.

Idle display

When traffic is near zero in both directions, the menu bar can optionally show your device name instead of "0 bps". Enable this in Settings → Display → Idle: Show Device Name.

3. Dashboard

Click the menu bar icon to open the dashboard popover. It shows everything about your current connection in one view.

Header

The status dot indicates connection health: green for connected, red for error, orange while starting up. The device name, interface, and SNMP version are shown below. A pin button in the top-right lets you detach the dashboard into a standalone window.

Rate cards

Two side-by-side cards show your current inbound and outbound bandwidth rates. If the app detects your interface's link speed, a utilization bar and percentage are shown below each rate.

Bandwidth chart

A history chart plots your inbound (cyan) and outbound (orange) rates over time. The time window is configurable: 5 minutes, 15 minutes, 30 minutes, or 1 hour.

Hover over the chart to see exact rates at any point in time
Click a legend label (In or Out) to isolate that series — click again to restore both

Stat cards

Optional cards appear below the chart. All are off by default — enable them in Settings → Stat Cards:

Packets per Second — inbound and outbound packet rates
Errors per Second — interface errors and discards (highlights yellow when errors are present)
Peak Rate — highest recorded rate with timestamp, over a configurable window (1h, 6h, 24h, or 7d)
Rolling Total — cumulative bytes transferred over a configurable window (1h, 6h, 24h, or 7d), with a "Since" date

Peak rates and rolling totals are persisted to disk and survive app restarts.

4. Pinned Panel

Click the pin icon in the dashboard header to detach it into a floating panel. The panel:

Stays visible when you switch to other apps
Persists across all Spaces
Can be moved anywhere on your desktop

Click the X button on the panel or the pin icon again to return to the popover mode. Left-clicking the menu bar icon toggles the panel's visibility.

5. Settings

Open Settings from the context menu (right-click the menu bar icon) or from within the dashboard. Settings are organized into five tabs.

Connection

Configure your SNMP device:

Device IP / Host — IP address or hostname
Custom Device Name — override the name reported by SNMP
SNMP Version — v1, v2c, or v3
Community String (v1/v2c) — defaults to public
Username, Auth Protocol, Auth Password (v3) — password is stored in the macOS Keychain
Interface Index — the interface to monitor. Use Discover... to browse all interfaces on the device
Poll Interval — how often to query the device (1s, 2s, 5s, 10s, 30s, 60s)
UDP Port — defaults to 161

The Test button (bottom bar) verifies connectivity and displays the device name on success.

Display

Bandwidth Unit — Auto (bits), Auto (bytes), Bits, or Bytes
Show Rates — Stacked, Inline, Out only, or In only
Chart Window — 5m, 15m, 30m, or 1h
Swap In / Out — reverses upload and download labels
Idle: Show Device Name — shows device name when traffic is near zero

Stat Cards

Toggle which stat cards appear on the dashboard: Packets per Second, Errors per Second, Peak Rate, and Rolling Total. Peak and Total cards have their own configurable history windows and reset buttons.

Alerts

Set inbound and outbound bandwidth thresholds. When exceeded, a macOS notification is sent. Notifications are rate-limited to once per minute per direction. Set a threshold to 0 to disable. See Alerts for details.

System

Appearance — System, Light, or Dark
Menu Bar Text Color — custom color for normal rates
Menu Bar Error Color — custom color when disconnected
Launch at Login — start automatically when you log in
iCloud Sync — sync settings across Macs. See iCloud Sync

About

Shows the app version, build number, and links to the Privacy Policy and License Agreement. Also includes copy-to-clipboard buttons for snmpwalk commands (v1, v2c, and v3) to help verify your device from Terminal.

Tip: Hover over any setting to see contextual help text at the bottom of the Settings window.

6. Connection Log

The Connection Log records every significant event: poll starts, successful connections, device info, warnings, and errors. Open it from the context menu or the dashboard.

Filter by level: All, Warnings, or Errors
Right-click any row to copy it to the clipboard
Export... saves the log as a plain text file
Clear removes all entries

The log auto-scrolls to the latest entry unless you've scrolled up to read older entries. It is capped at 500 entries to keep memory usage low.

Consecutive duplicate errors are deduplicated — the first 3 are logged, then every 30th — to prevent flooding during prolonged outages.

7. SNMP Data

The SNMP Data window shows raw per-poll counter values, deltas, computed rates, packet rates, and error rates. This is useful for verifying that your device is reporting correctly or diagnosing unexpected readings.

Sort order — toggle between Newest First and Oldest First
Errors Only — filter to show only failed polls
Show Suppressed — reveal zero-delta polls (hidden by default)
Right-click any row to copy the full row, or copy individual raw counter values
Export... saves the data as a CSV file

Capped at 1,000 records. The info button in the toolbar documents each column.

8. Alerts

FlowMoSNMP can send macOS notifications when your bandwidth exceeds a threshold you define.

Set thresholds independently for inbound and outbound traffic in Settings → Alerts
Choose your preferred unit: Kbps, Mbps, Gbps, KB/s, MB/s, or GB/s
Set a threshold to 0 to disable alerts for that direction

Notifications are rate-limited to one per direction per minute to avoid flooding. macOS will prompt for notification permission the first time you save a non-zero threshold.

9. iCloud Sync

Enable iCloud Sync in Settings → System to keep your configuration in sync across all your Macs.

Configuration data syncs via iCloud Key-Value Store
SNMPv3 passwords sync separately via iCloud Keychain — they are never stored in iCloud KV
Changes made on one Mac appear on your other Macs automatically
The System tab shows the last sync time and status

Remove Data from iCloud deletes your configuration from iCloud without affecting local settings on the current Mac.

Tip: If you install FlowMoSNMP on a new Mac, the onboarding window will detect your iCloud settings and offer to import them — no need to re-enter anything.

10. Exporting Data

Connection Log

Click Export... in the Connection Log window to save entries as a plain text file. The export respects your current filter (All, Warnings, or Errors).

SNMP Data

Click Export... in the SNMP Data window to save records as a CSV file. The export respects your current filter and sort settings.

Copy Stats

Right-click the menu bar icon and choose Copy Stats to Clipboard to copy a summary of your current rates, peak rates, and rolling totals as plain text.

11. Verifying Your Device via Terminal

Before installing the app, or to troubleshoot connectivity, you can use snmpwalk and snmpget in Terminal. Install with brew install net-snmp if needed.

Step 1 — Find your interface index

snmpwalk -v2c -c public 192.168.1.1 1.3.6.1.2.1.2.2.1.2

This lists each interface with a number. For example:

IF-MIB::ifDescr.1 = STRING: lo0
IF-MIB::ifDescr.2 = STRING: eth0
IF-MIB::ifDescr.3 = STRING: WAN

Step 2 — Verify all counters

Using the interface index (e.g., 3 for WAN):

snmpget -v2c -c public 192.168.1.1 \
  1.3.6.1.2.1.2.2.1.10.3 \
  1.3.6.1.2.1.2.2.1.16.3 \
  1.3.6.1.2.1.2.2.1.11.3 \
  1.3.6.1.2.1.2.2.1.17.3 \
  1.3.6.1.2.1.2.2.1.14.3 \
  1.3.6.1.2.1.2.2.1.20.3

This checks all six metrics: bytes in/out, packets in/out, and errors in/out. If all six return numeric values, every stat the app can display is supported.

Replace public with your community string and 192.168.1.1 with your device IP.

12. FAQ

Does FlowMoSNMP have to be running to capture data?

Yes. The app must be running and active in the menu bar to poll your device and collect bandwidth data. It does not run as a background service — if you quit the app, data collection stops. If your Mac goes to sleep, polling pauses and you'll see gaps in the chart and history when it wakes back up.

How many devices will this monitor at one time?

FlowMoSNMP monitors one device at a time. You configure a single SNMP host and interface, and the app polls that device continuously.

What devices have been tested to work?

Ubiquiti and Synology devices have been confirmed to work. In general, any device that supports standard SNMP interface counters (ifInOctets / ifOutOctets) should be compatible — including routers, switches, and NAS devices from most major vendors.

Do all devices support 1-second polling?

No. Some devices update their SNMP counters less frequently than once per second — commonly every 5 or 10 seconds. When polling faster than the device refreshes, you'll see zero-rate readings between real updates. FlowMoSNMP detects this pattern automatically and logs a notice to the Connection Log so you know what to expect from your device.

Does it keep running when I close the window?

Yes. FlowMoSNMP lives entirely in the menu bar — there is no Dock icon and no main window to close. Clicking the menu bar icon opens and closes the dashboard, but polling continues in the background the whole time.

Why does the menu bar show dashes or a timeout error?

This usually means the app can't reach your device. Check that the IP address and port are correct (default is 161), SNMP is enabled on the device, and your community string matches. The Connection Log shows the exact error to help narrow it down.

Where do I find my SNMP community string?

Log in to your router, switch, or NAS admin panel and look for an SNMP settings page. The community string is usually listed there — the default on most devices is public. For SNMPv3, you'll set a username and auth password in the same area.

What happens if my device goes offline?

The menu bar text turns orange to signal a problem, and each failed poll is recorded in the Connection Log with a timestamp. When the device comes back online, polling resumes automatically and the color returns to normal.

13. Troubleshooting

Menu bar shows dashes or a timeout error

The app cannot reach your device. Check that:

The IP address and port are correct (default SNMP port is 161)
SNMP is enabled on the device
Your community string matches the device's configuration
No firewall is blocking UDP traffic on port 161

Open the Connection Log for the exact error message.

Rates show zero even though there is traffic

Some devices update their SNMP counters less frequently than your poll interval (e.g., every 5 or 10 seconds). When polling faster than the device refreshes, you'll see zero-rate readings between real updates. FlowMoSNMP detects this automatically and logs a notice to the Connection Log with the estimated counter update interval.

The app shows "No Such Object" errors

The device doesn't support the requested counter on this interface index. Try:

A different interface index — use Discover... in Settings to browse available interfaces
Verify SNMP is enabled for the correct interface on the device

SNMPv3 authentication fails

Confirm your username, auth protocol (MD5 or SHA-1), and password match the device configuration
The auth password must be at least 8 characters
FlowMoSNMP supports authNoPriv security level — privacy/encryption is not currently supported

Memory usage grows over time

If you leave windows open (Settings, Connection Log, SNMP Data) for extended periods, SwiftUI may accumulate overhead. Close windows you're not actively using. The dashboard popover automatically releases its view tree when closed.

Resetting the app

To reset onboarding and start fresh, run this in Terminal:

defaults delete app.flowmosnmp.flowmosnmp hasCompletedOnboarding

Then relaunch the app.

This user guide was generated with the help of AI and reviewed by a human. We use AI to help keep the guide up to date as features change. While we review for accuracy, mistakes are still possible. If you notice something that doesn't look right, please email us at .

FlowMoSNMP User Guide