The default password on most managed switches from Netgear is admin / <no password>, maybe that's the issue?
If not and in case you have access to the serial console port, you may consider using the way via the boot menu menu which doesn't need reliable timing except for you to have the baud rate configured correctly and you hitting the key "q" at the right time.
I remember the M4100 having a small switch on the front where you'd have to switch between the Mini-USB console port on the front and the DB9 console port on the back. Output is show on both ports, but keyboard input is only accepted on one of the ports accordingly.
It is easier getting into the boot menu on the DB9 port since the USB port isn't recognized on your machine until the box has powered up - you can only connect to the console port once the port shows up on your local operating system. But I remember there is enough time to hit 'q' even on the USB port, but you may need 1 or 2 attempts.
Thank you for your reply. In my case, the switch was working just fine, I had the password and so forth. Suddenly, after about 4 months without any modifications, I needed to create a LAG, but, it was no longer reachable via the we interface on its assigned IP. I connected my serial cable and fired Putty, loaded my saved configurations I had used before and nothing. This model does not have a USB interface. It is either serial or web GUI. Neither of them is working to access. Yes, I know the default password is no password and it is not the case here, I cannot even get a serial connection.
Ok, unless you've changed the baud rate on the switch (unlikely) and/or have set the wrong COM port, those settings look fine to me. If you use a USB to serial converter: Some change their device registration when plugged into another USB port on the same computer and end up as different COM x(Windows) or ttyUSBx port (Linux). Since you use Putty (likely Windows), verify the device name in the Device Manager.
If you have another Netgear switch just to verify the serial cable and / or USB to serial converter works, that might be useful to.
Other than that I'd bite the bullet and make a hard power reset on the switch while leaving the console port connected. Let's hope it's just the mangement plane that has crashed. You might consider checking for a firmware update after a reboot though.
I've one run into a specific bug with M4300 where the stack master lost its network connectivity but remained accessible via serial console, but I've not encountered a Netgear switch losing its serial console completely though, but not impossible.
