ASA 5506-X "Error connecting with SSL. EOF was observed that violates the protocol"

[Dan Brook]

We have an ASA 5506-X at a remote site. A few days ago we noticed from out monitoring (PRTG) that the HTTPS/SSL sensors had failed. Then we found that we were unable to get onto the ASA via HTTPS/ASDM.

PRTG is telling us "Failed to establish secure connection [Step 0] Error connecting with SSL. EOF was observed that violates the protocol..."

I can't find much about this error specifically for ASAs, Cisco, etc.

If anyone can offer any suggestion of a fix or how to begin troubleshooting the issue it would be appreciated.

[mls577 · Accepted solution]

This could be a bug, I'd first try restarting the device. If that doesn't fix it, report back.

[Dan Brook]

That's all I can try I think. I very cautious about doing so in case there are other issues with the device and it doesn't come back up. The firewall is in another hemisphere so I can't just run down there with a new one. I'll reply back once it's been rebooted.

[mls577]

Sounds good. Also I know the error you're receiving from prtg. I've experienced it when it tries a https sensor, and the ASA's ssl settings were on lower, weaker ciphers.

[Dan Brook]

Well, a power outage on site has done the job for me. The ASA has booted back up and looks OK. I still don't know the reason for the error or why it stopped working so we are shipping a spare just in case.