I have two VMs running Ubuntu server 16.04 on the same host machine, let us call them A and B. They have different MAC addresses, which are both allowed on the network and can both access the Internet. I can use putty to ssh into both VMs. I can use B to ssh into A. However, I cannot use A to ssh into B, since I consistently get a "permission denied (password)" error. It doesn't even get to the point where it asks me to enter my username. The command I am running is:
ssh -p 6600 MY_IP
where I've added port forwarding from port 6600 to port 22, on which B listens to incoming ssh requests. Since putty can ssh into B, I assume this isn't an ssh setting issue.
Any ideas? I have installed openssh and I believe that's what I'm using.