From the man page for the configuration file for the Samba suite in the "client max protocol" section:

Possible values are :

  • CORE: Earliest version. No concept of user names.
  • COREPLUS: Slight improvements on CORE for efficiency.
  • LANMAN1: First modern version of the protocol. Long filename support.
  • LANMAN2: Updates to Lanman1 protocol.
  • NT1: Current up to date version of the protocol. Used by Windows NT. Known as CIFS.
  • SMB2: Re-implementation of the SMB protocol. Used by Windows Vista and later versions of Windows. SMB2 has sub protocols available.
  • SMB2_02: The earliest SMB2 version.
  • SMB2_10: Windows 7 SMB2 version.
  • SMB2_22: Early Windows 8 SMB2 version.
  • SMB2_24: Windows 8 beta SMB2 version.

By default SMB2 selects the SMB2_10 variant.

  • SMB3: The same as SMB2. Used by Windows 8. SMB3 has sub protocols available.
  • SMB3_00: Windows 8 SMB3 version. (mostly the same as SMB2_24)
  • SMB3_02: Windows 8.1 SMB3 version.
  • SMB3_10: early Windows 10 technical preview SMB3 version.
  • SMB3_11: Windows 10 technical preview SMB3 version (maybe final).

By default SMB3 selects the SMB3_11 variant.

Normally this option should not be set as the automatic negotiation phase in the SMB protocol takes care of choosing the appropriate protocol.

The value default refers to SMB3_11.

Adding clarification from A.B in the comments:

wiki.samba.org/index.php/Samba3/SMB2 states "Samba 3.6 added basic support for SMB2.0", "Basic support for SMB 2.1 was added in Samba 4.0.0", "Basic support for SMB3 is included in Samba 4.0.0 and later."

Answer from Jeff Schaller on Stack Exchange
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nixCraft
cyberciti.biz › nixcraft › howto › samba (smb/cifs) › how to configure samba to use smbv2 and disable smbv1 on linux or unix
How to configure Samba to use SMBv2 and disable SMBv1 on Linux or Unix - nixCraft
May 12, 2021 - Edit smb.conf file, run: $ sudo vi /etc/samba/smb.conf Find the [global] section and append the following line: min protocol = SMB2 Here is my updated file: Fig.01: How to force SMB2 protocol in samba on Linux or Unix The following seems to work with Windows 10/Linux clients too as noted by many in the comments section below: protocol = SMB2 For samba version 4.x, you can set protocol = SMB3 Save and close the file.
Top answer
1 of 1
16

From the man page for the configuration file for the Samba suite in the "client max protocol" section:

Possible values are :

  • CORE: Earliest version. No concept of user names.
  • COREPLUS: Slight improvements on CORE for efficiency.
  • LANMAN1: First modern version of the protocol. Long filename support.
  • LANMAN2: Updates to Lanman1 protocol.
  • NT1: Current up to date version of the protocol. Used by Windows NT. Known as CIFS.
  • SMB2: Re-implementation of the SMB protocol. Used by Windows Vista and later versions of Windows. SMB2 has sub protocols available.
  • SMB2_02: The earliest SMB2 version.
  • SMB2_10: Windows 7 SMB2 version.
  • SMB2_22: Early Windows 8 SMB2 version.
  • SMB2_24: Windows 8 beta SMB2 version.

By default SMB2 selects the SMB2_10 variant.

  • SMB3: The same as SMB2. Used by Windows 8. SMB3 has sub protocols available.
  • SMB3_00: Windows 8 SMB3 version. (mostly the same as SMB2_24)
  • SMB3_02: Windows 8.1 SMB3 version.
  • SMB3_10: early Windows 10 technical preview SMB3 version.
  • SMB3_11: Windows 10 technical preview SMB3 version (maybe final).

By default SMB3 selects the SMB3_11 variant.

Normally this option should not be set as the automatic negotiation phase in the SMB protocol takes care of choosing the appropriate protocol.

The value default refers to SMB3_11.

Adding clarification from A.B in the comments:

wiki.samba.org/index.php/Samba3/SMB2 states "Samba 3.6 added basic support for SMB2.0", "Basic support for SMB 2.1 was added in Samba 4.0.0", "Basic support for SMB3 is included in Samba 4.0.0 and later."

Discussions

client min protocol = SMB2 client max protocol = SMB3
Bei Zugriff auf Windows10 Shares sind bei einigen Windows10 Installationen folgende Samba-Optionen notwendig: [global] client min protocol = SMB2 client max protocol = SMB3 Zudem ist die options "s... More on github.com
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1
March 25, 2018
networking - Set SMB2 protocol in Samba 3.6.6 - Unix & Linux Stack Exchange
And because now min protocol is higher than max, smbd actually cannot allow any protocol at all. The facts that SLES 11.4's Samba is so old and its SMBv3 support seems to be buggy (as you discovered) caused us to make it a priority at work to upgrade any Samba servers that were still running SLES 11.4 to SLES 12 or newer. ... running Samba-3.6.3 in SLES 11.4 which has kernel 3.0, my global section is this and I know SMB2 works because windows 10 ... More on unix.stackexchange.com
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November 7, 2018
Is it possible to Enable ONLY SMB3, while disabling SMB1 and SMB2 on Windows 10 21H2?
I think smb2 and smb3 use the same stack so you can't just disable one and not the other, doesn't smb3 support encryption? You might be able to limit the connections that way? "When you enable or disable SMBv2 in Windows 8 or Windows Server 2012, SMBv3 is also enabled or disabled. This behavior occurs because these protocols share the same stack." More on reddit.com
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29
26
March 18, 2025
Solved - Per-host "min protocol" in samba? | The FreeBSD Forums
I've recently set our samba server at work to use "server min protocol = SMB2", as some of our Windows clients were using older dialects to communicate. Samba 4.10 (and possibly earlier versions) seem to have some issues with the older standards, and there are security benefits to having this... More on forums.freebsd.org
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October 7, 2019
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Bobcares
bobcares.com › blog › your-system-requires-smb2-or-higher-how-to-resolve-windows-error
Your system requires smb2 or higher – How to resolve Windows error
March 26, 2021 - [global] server min protocol = SMB2_10 client max protocol = SMB3 client min protocol = SMB2_10 encrypt passwords = true restrict anonymous = 2
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GitHub
github.com › mschlenstedt › Loxberry › issues › 676
client min protocol = SMB2 client max protocol = SMB3 · Issue #676 · mschlenstedt/Loxberry
March 25, 2018 - Bei Zugriff auf Windows10 Shares sind bei einigen Windows10 Installationen folgende Samba-Optionen notwendig: [global] client min protocol = SMB2 client max protocol = SMB3 Zudem ist die options "syslog" obsolete. Diese sollte entfernt w...
Author   mschlenstedt
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Top answer
1 of 2
1

SLES 11.4 is old enough for its Samba to default to SMBv1 only. You've set both client min protocol and client max protocol, which only affect Samba when it's acting as a client, like smbclient.

For server-side, you've only set server min protocol, so the server max protocol is still defaulting to SMBv1. And because now min protocol is higher than max, smbd actually cannot allow any protocol at all.

The facts that SLES 11.4's Samba is so old and its SMBv3 support seems to be buggy (as you discovered) caused us to make it a priority at work to upgrade any Samba servers that were still running SLES 11.4 to SLES 12 or newer.

2 of 2
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running Samba-3.6.3 in SLES 11.4 which has kernel 3.0, my global section is this and I know SMB2 works because windows 10 client will NOT connect via SMB1 the minimum is SMB2 for win10 out of the box.

Note that if you set Min Protocol = SMB2 then if your clients are Windows 7 it will not work for them... at least i did not figure it out troubleshooting on the windows side I think for Win7 it is default SMB1 unless you manually configure something in win7 to say do SMB2.

And for whatever reason setting max protocol = SMB3 caused things not to work for me thus I have SMB2 specified.

[global]
    min protocol = SMB2
    max protocol = SMB2
    workgroup = workgroup
    passdb backend = tdbsam
    map to guest = Never
    usershare allow guests = No
    add machine script = /usr/sbin/useradd  -c Machine -d /var/lib/nobody -s /bin/false %m$
    domain master = No
    security = user
    wins support = No
    server signing = auto
    name resolve order = lmhosts bcast host
    printing = bsd
    printcap name = /dev/null
    log level = 2 auth:10 auth_audit:3 auth_json_audit:3 winbind:5
    max log size = 1000000

and a sample of a share that i use

[data1]
    create mask = 660
    directory mask = 770
    inherit acls = Yes
    path = /data1
    read only = No

you should not need to do anything in /etc/fstab other than mounting your storage resource as you normally would. Then once mounted make sure access permissions of that folder... chmod 777 /data1 in my example, are open for starters, then when working go ahead and remove world permissions and change group ownership and permissions as you need.

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Google Groups
groups.google.com › g › reading-hackspace › c › 2tUCvIhf8kg
Samba SMB1/SMB2 share issues in Windows 10
I would think that nas_configgen is only run when a new SMB share is created. I suggest having a look at /etc/samba/samba.conf see if the "min protocol = SMB2" or "server min protocol = SMB2" is set.
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Twardziel
twardziel.eu › it › 3-min-max-protocol-in-smb.conf.pdf pdf
Understanding min and max protocol levels in smb.conf
1. client min protocol – This setting controls the minimum protocol version that the client will ... SMB2_02: The earliest SMB2 version. ... SMB2_10: Windows 7 SMB2 version.
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Reddit
reddit.com › r/sysadmin › is it possible to enable only smb3, while disabling smb1 and smb2 on windows 10 21h2?
r/sysadmin on Reddit: Is it possible to Enable ONLY SMB3, while disabling SMB1 and SMB2 on Windows 10 21H2?
March 18, 2025 - We had to do some of this for troubleshooting specific versions of SMB2. https://techcommunity.microsoft.com/blog/filecab/controlling-smb-dialects/860024 · HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanWorkstation\Parameters ... My first guess would be Windows 10 LTSC, it's frozen to that version. ... That’s not a matter of the client but of the server — you want smb3 only, don’t share files via some other protocol version.
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Ixsystems
redmine.ixsystems.com › issues › 24334
Bug #24334: SBM server errors using min protocol SMB2 - FreeNAS - iXsystems & FreeNAS Redmine
March 11, 2020 - Windows 2008 clients seem use a maximum version of SMBv2.02, version SMBv2.10 appears to not be implemented. Setting the FreeNAS server to "SMB2_02" for the minimum protocol fixed the issue with Windows clients, and Linux clients can also mount the share with the "vers=2.0" option.
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Microsoft Learn
learn.microsoft.com › en-us › windows-server › storage › file-server › manage-smb-dialects
Manage SMB dialects in Windows and Windows Server 2025 | Microsoft Learn
November 1, 2024 - Here's how to configure the minimum and maximum SMB dialects for the SMB client using PowerShell using the Set-SmbClientConfiguration cmdlet: From an elevated PowerShell prompt, run the following commands: Set-SmbClientConfiguration -Smb2DialectMax {SMB202 | SMB210 | SMB300 | SMB302 | SMB311 | None} -Smb2DialectMin {None | SMB202 | SMB210 | SMB300 | SMB302 | SMB311}
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Samba
lists.samba.org › archive › samba › 2019-July › 224586.html
[Samba] client min protocol = SMB2
July 22, 2019 - If all the users are using MS Windows PC's then this is not relevant. Regardless of how the the client is set, as long as the servers enforce min protocol of SMB2 or higher then you should be OK. SMB1 and older protocols are not considered secure. On 7/22/19 11:22 AM, Edouard Guigné via samba wrote: > Hello, > > Thank you ! > > I add server min protocol = SMB2_02 to smb.cnf > > All clients are now using SMB2_10 ...
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Microsoft Learn
learn.microsoft.com › en-us › openspecs › windows_protocols › ms-smb2 › 5606ad47-5ee0-437a-817e-70c366052962
[MS-SMB2]: Server Message Block (SMB) Protocol Versions 2 and 3 | Microsoft Learn
Specifies the Server Message Block (SMB) Protocol Versions 2 and 3, which support the sharing of file and print resources between machines and extend the concepts from the Server Message Block Protocol.
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MajorGeeks
majorgeeks.com › tutorials and video guides › how to enable or disable smbv2 in windows 10 & 11
How to Enable or Disable SMBv2 in Windows 10 & 11 - MajorGeeks
June 15, 2023 - Open the Powershell and type in Get-SmbServerConfiguration | Select EnableSMB2Protocol. You should receive a True in response, meaning you can run SMB2 on your computer. If not, you might need to be sure you have the latest build of Windows.
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Gen
support.gen.uk › kb › faq.php
Setting SMB Versions in Samba Server - GEN HelpDesk
Setting server min/max protocol (and optionally the client equivalents) in smb.conf lets you harden your Samba server against the outdated and insecure SMB1 protocol while still supporting the modern SMB2/SMB3 dialects used by Windows 10/11 and recent Linux clients.
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Total Commander
ghisler.ch › home › index › total commander › total commander (english)
Cannot connect to SMB server when min protocol = SMB2 is set - Total Commander
May 18, 2017 - Good news: The first beta with SMB2 support is available now! It contains both the old SMB1 support (via JCIFS) and the new SMB2 support (via SMBJ). IMPORTANT: You need to enable SMB2 via connection settings checkbox, there is currently no automatic detection.
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FreeBSD
forums.freebsd.org › server and networking › web and network services
Solved - Per-host "min protocol" in samba? | The FreeBSD Forums
October 7, 2019 - I've recently set our samba server at work to use "server min protocol = SMB2", as some of our Windows clients were using older dialects to communicate. Samba 4.10 (and possibly earlier versions) seem to have some issues with the older standards, and there are security benefits to having this...