IBM Support

QRadar: Failed to Add the Host to the List of Known Hosts (/root/.ssh/known_hosts)

Troubleshooting


Problem

This error can be observed attempting to disable strict host checking:
[root@Source ~]# ssh <Target_Host_IP> -o StrictHostKeyChecking=no

Failed to add the host to the list of known hosts (/root/.ssh/known_hosts).
root@<Target_Host_IP>'s password: 
Register this system with Red Hat Insights: insights-client --register
Create an account or view all your systems at https://red.ht/insights-dashboard
Last login: Wed May 28 13:21:47 2025 from aa.aa.aaa.160
[root@Target~]#

Symptom

On setup of ssh connectivity between two hosts for the first time, following error might be observed:
  
[root@Source ~]# ssh <Target_Host_IP>

No ECDSA host key is known for <Target_Host_IP> and you have requested strict checking.
Host key verification failed.
The resolution is provided in this document: 

QRadar: SSH to host fails with error "No ECDSA host key is known for <Remote Host IP> and you have requested strict checking"

But, the workaround gives the following error and asks for the strict host checking again and again whenever you try to ssh:
 
[root@Source ~]# ssh <Taget_Host_IP> -o StrictHostKeyChecking=no

Failed to add the host to the list of known hosts (/root/.ssh/known_hosts).

root@<Taget_Host_IP>'s password: 
Register this system with Red Hat Insights: insights-client --register
Create an account or view all your systems at https://red.ht/insights-dashboard
Last login: Wed May 28 13:21:47 2025 from aa.aa.aaa.160
[root@Target ~]#

Document Location

Worldwide

[{"Type":"MASTER","Line of Business":{"code":"LOB77","label":"Automation Platform"},"Business Unit":{"code":"BU048","label":"IBM Software"},"Product":{"code":"SSBQAC","label":"IBM Security QRadar SIEM"},"ARM Category":[{"code":"a8m0z000000cwtNAAQ","label":"Deployment"}],"ARM Case Number":"","Platform":[{"code":"PF016","label":"Linux"}],"Version":"7.5.0"}]

Log InLog in to view more of this document

This document has the abstract of a technical article that is available to authorized users once you have logged on. Please use Log in button above to access the full document. After log in, if you do not have the right authorization for this document, there will be instructions on what to do next.

Document Information

Modified date:
11 June 2025

UID

ibm17235011

Page Feedback