> For the complete documentation index, see [llms.txt](https://ret2basic.gitbook.io/ctfnote/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://ret2basic.gitbook.io/ctfnote/red-teaming/enumeration/service-enumeration/netbios.md).

# NetBIOS

## What is NetBIOS?

NetBIOS allows applications on different systems to communicate with one another over the LAN. It is used for:

* Sharing printers and files
* Remote procedure calls
* Exchange messages
* ...

If NetBIOS is not properly configured, it can leak:

* Computer names
* Usernames
* Domains
* Printers
* Available shares
* ...

## NetBIOS Enumeration

NetBIOS uses the following ports:

* **UDP 137: name services**
* **UDP 138: datagram services**
* **TCP 139: session services**

## Reference

{% embed url="<https://book.hacktricks.xyz/pentesting/137-138-139-pentesting-netbios>" %}
Pentesting NetBios - HackTricks
{% endembed %}