OneLinersCommand workbench
Verified diagnostic signature

SSH could not validate or negotiate the server host key.

Match output from ssh, understand the likely cause, then continue with sourced, read-only checks.

Confidence
high
Platforms
linux · macos · windows
Verified
2026-07-24
Recognized output

Signature matched locally

Offending .* key in

OneLiners matches this pattern in your browser. Your pasted output is not stored or indexed.

Likely causes

What usually produces this signal

  1. Legitimate host rebuild
  2. Stale known_hosts entry
  3. Unsupported algorithm
  4. Possible interception
Safe next checks

Collect evidence before changing the system

01

Show the effective OpenSSH client configuration for a host

ssh -G <host> | sort

The output matches the expected target and exits without an error.

02

Diagnose an SSH connection without opening an interactive shell

ssh -vvv -o BatchMode=yes -o ConnectTimeout=10 <username>@<host> true

Re-run the corresponding read-only inspection and confirm the intended state.

03

Fetch the SSH host keys offered by a server

ssh-keyscan -H -p <port> <host>

The output matches the expected target and exits without an error.