Hello Emil_G,
Yes the topology is still valid.
That means the MGT PC is connected to the 8P Management switch, on an untagged port in VLAN 100. - Correct.
The 8P Management switch also has 2 connections to the firewall, one for VLAN 300 and another for VLAN 100. - Correct
Are this 2 physical ports or it is a single physical port with 2 VLANs tagged on it? - 2 physical ports.
The connection between the 8P and the 16P switch carries only VLAN 300. - Correct
Does the 8P Management switch has its management IP in VLAN 300 or in VLAN 100? - I've set one management IP in each VLAN.
If this is still the topology I cannot understand why adding a default gateway on the 16P Core should affect connectivity between the MGT PC and 8P switch. This traffic shouldnt traverse the 16P Core at all no matter if it is switched or routed.
Or do you actually mean that you are trying to SSH from the CLI of the 16P core switch to the 8P management switch and its not working? - Negative. I am able to ssh from the 16P core switch to the 8P management switch but not able to ssh into the 8p management switch.
I had just tested the following
I have pretty much identical configuration for both the 16P and the 8P.
Removed ethernet connection between 16P and 8P. Now I can SSH into the 8P from my Mgt PC, of course I can't SSH into the 16P any more.
I've reloaded the SSH keys (via crypto) just in case but nothing is helping.
I shut down everything and then rebooted the two switches. Went for a long walk.
I can now log into both the switches from the MGT PC. I have no idea why this is happening. I'll monitor this for the next couple days.