---
title: "netbiosd on Mac: NetBIOS names and local network traffic · Kilobat Guides"
url: "https://kilobat.app/guides/what-is-netbiosd.html"
description: "netbiosd handles NetBIOS names for Windows file sharing on a Mac. Learn why it sends local network traffic and which sharing settings affect it."
---

macOS processes

# What is netbiosd on Mac?

`netbiosd` handles NetBIOS names for Windows-style networks. Its traffic stays on the local network.

Process: `netbiosd` · Applies to: All current macOS versions. Seen on macOS 27.2. · Checked: 29 October 2026

## Where you see it

- `netbiosd` is in the list in Activity Monitor › Network, in `nettop` or in Kilobat.
- A firewall or network monitor asks if `netbiosd` can connect.
- Small, regular traffic on the local network.

## What it is

The man page says that netbiosd registers and defends NetBIOS names. It also browses names on the network and gives them to the system through mDNSResponder.

Its configuration comes from the SMB file sharing settings of the Mac.

## Why it uses the network

- **Name registration.** It registers the Mac's NetBIOS name on the local network.
- **Browsing.** It looks for other computers and workgroups on the network.

## Is it normal?

Yes. Small local traffic is usual. It does not use your internet connection.

## See how much it uses

1. Open Activity Monitor from Applications > Utilities. Click Network.
2. Type `netbiosd` in the search field. The Sent Bytes and Rcvd Bytes columns show what it moved.
3. In Terminal, watch only this process. Press d to show the change per second, and q to quit.

   ```
   nettop -p netbiosd -P
   ```

## Reduce or pause it safely

1. If you do not share files with Windows computers, check File Sharing. Choose Apple menu > System Settings > General > Sharing.
2. Turn off File Sharing if you do not use it. The netbiosd man page says that its configuration comes from the SMB settings.
3. Do not quit `netbiosd` in Activity Monitor. It is part of macOS, and other features depend on it.

## With Kilobat

1. Open the Kilobat app list and search for `netbiosd`. Its row shows the live rate and the bytes it moved.
2. Kilobat shows local network traffic apart and does not count it as Internet data.
3. In Terminal, see the same live list. Press / and type the name to search.

   ```
   kilobat status --watch
   ```
4. Show its traffic over one day. Names match `kilobat report --summary`.

   ```
   kilobat bandwidth netbiosd day
   ```
5. Through MCP, an AI agent gets the same history with `get_app_bandwidth` and the name `netbiosd`.
6. The live view is free. History in the app needs Pro. Kilobat records history only while the app runs.

## Questions

**Does netbiosd send data to the internet?**

The man page describes only NetBIOS on the local network.

## Sources

- netbiosd(8) and mDNSResponder(8), man page installed with macOS 27.2
- [RFC 1001: NetBIOS service on TCP/UDP, concepts and methods](https://www.rfc-editor.org/rfc/rfc1001)
- nettop(1), man page installed with macOS 27.2

Sources checked on 29 October 2026. Man pages are the ones installed with macOS; open one with `man <name>` in Terminal.

## Related guides

- [What is mDNSResponder on Mac?](https://kilobat.app/guides/what-is-mdnsresponder.html): mDNSResponder answers DNS lookups for every app on the Mac, and it runs Bonjour on the local network.
- [Find the devices on your local network from a Mac](https://kilobat.app/guides/find-devices-on-network.html): macOS has two built-in ways to see other devices: the ARP table and Bonjour.
- [The macOS firewall blocks incoming connections](https://kilobat.app/guides/macos-firewall-incoming.html): The macOS firewall controls connections that other computers start to your Mac.