I'll expand this to something more comprehensive later but mainly wanted to record something odd that happened to me using Gentoo.

When PasswordAuthetication=no is ignored

Set KeyboardInteractive to no

PasswordAuthentication no
KbdInteractiveAuthentication no

Cisco Switch options

Set these options in $HOME/.ssh/config to be able to ssh onto Cisco switches. Shown where "switch" is the DNS hostname for the switch in question. If you aren't using DNS use an IP address here.

Host switch
    KexAlgorithms +diffie-hellman-group1-sha1
    HostkeyAlgorithms +ssh-rsa
    Ciphers +3des-cbc
    ForwardX11 no