Data Domain: How to Disable SMBv1
Summary: SMB v1 and SMBv2 are by enabled by default on Data Domain system. However, starting from DDOS 6.1.2.20 SMBv1 can be disabled on Data Domain.
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Symptoms
SMB1 isn t modern or efficient
When you use SMB1, you lose key performance and productivity optimizations for end users and its also a security vulnerability.
Cause
SMB Signing on Data Domain
Resolution
Execute the following steps in the CLI as sysadmin (or a user with equal rights):
# cifs option show all
Verify if SMBv1 is enabled
All Options:
Option Value
----------------------------------- -------------
idmap-type rid
domain-account-mmc-share-management enabled (*)
idle-timeout 1800 (*)
loglevel 1 (*)
max-global-open-files 30000 (*)
max-mpx-count 50 (*)
max-tcp-connections 600 (*)
organizational-unit Computers (*)
restrict-anonymous disabled (*)
server-signing disabled (*)
tcp-window-size 1048576 (*)
support-smb1 enabled (*) <<<<<< Note: SMB1 is enabled.
support-smb2 enabled (*)
----------------------------------- -------------
(*) default value
Use the following command to disable SMBv1:
# cifs option set "support-smb1" "disabled"
To verify SMBv1 is disabled, execute below command
# cifs option show all
All Options:
Option Value
----------------------------------- -------------
idmap-type rid
domain-account-mmc-share-management enabled (*)
idle-timeout 1800 (*)
loglevel 1 (*)
max-global-open-files 30000 (*)
max-mpx-count 50 (*)
max-tcp-connections 600 (*)
organizational-unit Computers (*)
restrict-anonymous disabled (*)
server-signing disabled (*)
tcp-window-size 1048576 (*)
support smb1 disabled <<<<< smb1 is disabled, but cifs needs to be restarted to take effect.
support-smb2 enabled (*)
----------------------------------- -------------
(*) default value
Restart CIFS by using below commands
# cifs disable
# cifs enable
# cifs option show all
Verify if SMBv1 is enabled
All Options:
Option Value
----------------------------------- -------------
idmap-type rid
domain-account-mmc-share-management enabled (*)
idle-timeout 1800 (*)
loglevel 1 (*)
max-global-open-files 30000 (*)
max-mpx-count 50 (*)
max-tcp-connections 600 (*)
organizational-unit Computers (*)
restrict-anonymous disabled (*)
server-signing disabled (*)
tcp-window-size 1048576 (*)
support-smb1 enabled (*) <<<<<< Note: SMB1 is enabled.
support-smb2 enabled (*)
----------------------------------- -------------
(*) default value
Use the following command to disable SMBv1:
# cifs option set "support-smb1" "disabled"
To verify SMBv1 is disabled, execute below command
# cifs option show all
All Options:
Option Value
----------------------------------- -------------
idmap-type rid
domain-account-mmc-share-management enabled (*)
idle-timeout 1800 (*)
loglevel 1 (*)
max-global-open-files 30000 (*)
max-mpx-count 50 (*)
max-tcp-connections 600 (*)
organizational-unit Computers (*)
restrict-anonymous disabled (*)
server-signing disabled (*)
tcp-window-size 1048576 (*)
support smb1 disabled <<<<< smb1 is disabled, but cifs needs to be restarted to take effect.
support-smb2 enabled (*)
----------------------------------- -------------
(*) default value
Restart CIFS by using below commands
# cifs disable
# cifs enable
Additional Information
SMB2 must remain enabled.
Affected Products
Data DomainProducts
Data DomainArticle Properties
Article Number: 000055372
Article Type: Solution
Last Modified: 29 Jul 2025
Version: 3
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