Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

NX-OS only allows logins on even numbered attempts

I am having a strange issue with my MDS 9148. We are running NX-OS 5.2 (6a).

When I attempt to log into the switch via SSH, the initial login password will be rejected, even if it is correct. The second login attempt will be accepted.

If you make a mistake on the second login attempt, the third attempt is also rejected, even if correct. In short, odd numbered login attempts (1st, 3rd) are rejected out of hand, and you can only log into the switch on even numbered attempts (2nd, 4th).

My test automation is impacted by this issue as we need to log into the seed switch to do command line zoning to access our targets and test our driver stacks with storage IO to FC luns.

I have stopped the SSH server and restarted it.

I have stopped the SSH server, deleted the SSH key, regenerated the SSH key, and restarted the SSH Server

I have rebooted the switch.

So far no luck in changing this behavior. I suppose I could try a firmware upgrade, but I want to be sure I need to do that before going down that path.

Any ideas?

  • Storage Networking
Cisco Employee

NX-OS only allows logins on even numbered attempts


The fix for this bug, might fix the issue you have.

NX-OS 5.2(6b) Release Notes


Symptom: The first SSH login on a Cisco MDS 9100 or 9200 Series switch always fails.

Workaround: This issue is resolved



New Member

NX-OS only allows logins on even numbered attempts

Nice. I'll give this a try and report back.

This widget could not be displayed.