VxRail: Cannot Establish an SSH Session from VxRail Manager to vCenter: No Matching Mac Found

Summary: When trying to establish an ssh session from VxRM to vCenter, the connection fails with error: Unable to negotiate with port 22: no matching MAC found. Their offer: ...

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Symptoms

Trying to ssh to vCenter fails with the following error [MACs may vary according to the environment] 
Unable to negotiate with xxx.xxx.xxx.xxx port 22: no matching MAC found. Their offer: hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512,hmac-sha2-256

Cause

The root cause of this issue is the missing MACs in /etc/ssh/ssh_config that does not match the same MACs in ssh_config file on the vCenter virtual machine (VM).

VxRail Manager's ssh_config: 

Screenshot of ssh_config on VxRM 

vCenter's ssh_config:

Screenshot of ssh_config on vCenter

 

Resolution

Caution: Make a copy of ssh_config in VxRM and take a snapshot of the VxRail Manager.
 
  1. Login as root to both the VxRM and vCenter. 
  2. From the VxRM SSH, run this command to make a backup copy of the file: 
    cp /etc/ssh/ssh_config /home/mystic/ssh_config.bak
  3.  On vCenter output the contents of the file using: 
    cat /etc/ssh/ssh_config

     

  4. Copy the MACs from vCenter ssh_config file to VxRM ssh_config file. Edit the file using this command on VxRM: 
    vi /etc/ssh/ssh_config
  5. Restart SSHD on VxRM: 
    systemctl restart sshd
  6. Trying to establish ssh to vCenter from VxRM is successful 
    Screenshot of successful SSH 


 

Affected Products

VxRail, VxRail Appliance Family, VxRail Appliance Series, VxRail Software
Article Properties
Article Number: 000196038
Article Type: Solution
Last Modified: 16 Oct 2025
Version:  2
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