[sudo-users] When having multiple simultanious SSH connections, only the first two can `sudo`

[Todd C. Miller]

I'm not sure why sudo is not asking for a password for the other
two ptys.  Unless there is an entry in the timestamp file that has
not yet expired, you should be prompted for a password, even if the
password field in /etc/shadow is empty.

If you never want to have to authenticate with a password, why not
just disable authentication in sudo entirely?  A line like:

Defaults !authenticate

in /etc/sudoers will do the trick.

 - todd