FlowMoSNMP Help

FlowMoSNMP monitors SNMP-enabled network devices and shows live In/Out bandwidth in the menu bar and a desktop window. It polls each device's interface counters and computes byte and packet rates, handling 32-bit and 64-bit counter wrap-around.

Getting started

Add a device with File › Add Device (or the menu-bar menu), entering its host, SNMP version and community string or v3 credentials, and the interface index to monitor. Use Discover to list the device's interfaces and pick one by name. Once polling starts, the dashboard shows live rates, a bandwidth history chart, and optional stat cards.

SNMP versions

v1, v2c, and v3 (authNoPriv with MD5 or SHA-1) are supported. For v3, the auth password is stored in your Mac's Keychain, never in plain config.

Menu bar & window

Run FlowMoSNMP as a menu-bar app, a regular Dock window, or both — toggle the Dock icon and menu-bar icon in Settings › Display. With more than one device, pick which one drives the menu-bar reading from the status-item right-click menu.

Dashboard & stat cards

The dashboard shows the current In and Out rate, a history chart, and a row of stat cards you can turn on or off in Settings › Stat Cards: peak rates, rolling 24-hour totals, average rate, packet rates, and errors.

Errors counts true interface faults (ifInErrors / ifOutErrors) only — normal packet discards are tracked separately and never inflate the error total. The chart's Y-axis auto-scales to the busiest direction in the visible window.

Tip: Rate smoothing (Settings › Display) evens out the display when a device updates its counters less often than your poll interval — the underlying numbers stay exact in the SNMP Data table.

Connection Log

The Connection Log records timestamped SNMP events for a device — connects, restarts, diagnostics, and errors. Filter by level with the All / Warnings / Errors menu, and use the toolbar Search to find an entry. Timestamps are local time; the log is saved to a local database and persists across app restarts.

INFO Polling started: Logged when the app first connects or restarts polling after a settings change. Shows the host, port, and interface index being polled.
INFO Polling restarted: Logged when a settings change requires a fresh start (host, port, interface index, SNMP version, or credentials). The live In/Out rates and chart are always cleared. If you changed the host or interface index, Peak and Total are also reset; otherwise they are restored from the saved history for that device. The device name and HC/32-bit counter type are re-detected on the next poll.
INFO Connected / Connection restored: First successful poll response received, or recovery after one or more consecutive errors.
INFO Device name changed: FlowMoSNMP re-reads the device's sysName each poll, so a rename on the device is picked up automatically. A custom name you set in the app always wins and suppresses this.
WARN HC counters not supported: The device doesn't support 64-bit high-capacity (HC) counters. FlowMoSNMP falls back to 32-bit counters, which wrap at ~4 GB and may produce brief spikes on very fast links.
INFO Counter granularity: Logged once when the app detects that the device updates its SNMP counters less frequently than the poll interval. This is normal for many devices — the computed rates are still accurate, but they refresh at the device's counter-update rate rather than at your configured poll interval.
ERROR Poll error: The SNMP request failed — timeout, authentication failure, unreachable host, or no such OID. The first 3 consecutive errors are logged; after that, every 30th error is logged to avoid flooding. A brief failure right after the Mac wakes from sleep is ridden out for a few seconds before the device is shown as disconnected.

Export the visible entries to a text file with Export…, or clear the log with Clear.

SNMP Data

The SNMP Data table shows the raw per-poll counter values behind the computed rates — useful for validating accuracy against your device and diagnosing counter behavior. Sort with Newest / Oldest, narrow with the Filter menu, and find a value with the toolbar Search.

Columns

Time: Timestamp of the poll response.
Type: HC = 64-bit ifHCInOctets / ifHCOutOctets (preferred; no wrap below ~150 Tbps). 32 = 32-bit ifInOctets / ifOutOctets (wraps at ~4 GB, roughly every 34 s at 1 Gbps).
Raw In / Raw Out: The actual counter value returned by the device, shown in hex. Compare these directly with your router's MIB walk to verify accuracy.
ΔIn / ΔOut: Bytes transferred since the previous poll (counter delta). The In/Out direction matches the dashboard — the Swap In/Out setting is applied.
Rate In / Rate Out: Bandwidth computed from the delta: (ΔBytes × 8) ÷ elapsed time. Shown in the same unit as the dashboard.
Elap(s): Seconds elapsed between this poll and the previous one. Should closely match your configured poll interval; a large gap indicates a missed poll or timeout.
Pkt/s In / Pkt/s Out: Unicast packets per second derived from ifInUcastPkts and ifOutUcastPkts. Shows — if the counters were unavailable.
Err In / Err Out: Interface errors counted this poll, from ifInErrors / ifOutErrors — true faults (CRC, framing, etc.). Values greater than 0 are shown in red. These are what the Errors stat card and alerts count.
Disc In / Disc Out: Packets discarded this poll, from ifInDiscards / ifOutDiscards — usually normal buffer drops, not faults. Shown in amber when greater than 0 and tracked separately from errors.

Reading the table

The first row after a start or restart shows raw counter values but no delta or rate — there is no previous sample to subtract from. Rows for failed polls show the error message in place of the counters. A dash (—) in any column means that value was unavailable for that poll.

Rows with zero byte deltas are hidden by default. Some devices update their SNMP counters less frequently than the poll interval, so consecutive polls return the same value — rates are still accurate, they just appear less often. Turn on Show Suppressed in the Filter menu to see these dimmed rows. Error and discard counts are still recorded on suppressed rows, since they often increment on a poll where the byte counters didn't move.

Export every visible row (plus a trailing error column) to CSV with Export….

Privacy & sync

Everything stays on your device. Logs, history, and SNMP data live in a local database; nothing is uploaded to FlowMoSNMP. Device configurations can optionally sync across your Macs through your own private iCloud database (end-to-end encrypted) — sync is off until you turn it on in Settings.

Full details are in the Privacy Policy.