> For the complete documentation index, see [llms.txt](https://docs.duplicati.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.duplicati.com/backup-destinations/standard-based-destinations/cifs-aka-smb-destination.md).
# SMB (aka CIFS) Destination
This page describes the CIFS storage destination
{% hint style="info" %}
The destination can be selected with both `smb://` and `cifs://`. The `cifs://` name is deprecated and only kept for existing configurations; use `smb://` for new backups.
{% endhint %}
The Server Message Block (SMB) / Common Internet File System (CIFS) backend provides native support for accessing shared network resources using the SMB/CIFS protocol. This backend enables direct interaction with Windows shares and other SMB-compatible network storage systems.
## User interface
To use the SMB connection you must supply the server, shared name, path on server, username, password, and transport. See below for a description of the transport method.
## URL format for Commandline
To use the CIFS destination, you can use a url such as:
```
smb:////
?auth-username=
&auth-password=
&transport=directtcp
```
If the account belongs to a Windows domain, enter the domain in the user interface, or add `&auth-domain=` to the URL.
## Transport
SMB supports two distinct transport protocols, each with its own characteristics:
#### DirectTCP (directtcp)
* **Port**: 445
* **Characteristics**:
* Faster performance
* Modern implementation
* Preferred for newer systems
* Direct TCP/IP connection
* Lower overhead
#### NetBIOS over TCP (netbios)
* **Port**: 139
* **Characteristics**:
* Legacy support
* Compatible with older systems
* Additional protocol overhead
* Slower performance
* Uses NetBIOS naming service
## Advanced Options
\--[**read-buffer-size**](#user-content-fn-1)[^1]
Defines the read buffer size, in bytes, for SMB operations (Will be capped automatically by SMB negotiated values, values below 10000 bytes will be ignored)
\--[**write-buffer-size**](#user-content-fn-1)[^1]
Defines the write buffer size, in bytes, for SMB operations (Will be capped automatically by SMB negotiated values, values below 10000 bytes will be ignored)
The SMB backend is available on stable release from version 2.2.
[^1]: Manual buffer size adjustment is typically unnecessary and not recommended as it may interfere with the protocol's built-in optimization. The default negotiation process ensures optimal performance for most use cases.
---
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