ssh server doesn't allow outside connections

I'm not sure which update broke it for me, but I can no longer ssh to a machine booted into SystemRescueCD. I set the root passowrd and I (re)started sshd. I can ping the computer just fine, but ssh times out before any connection is made. sshing to it works when booted into another live distribution, such as Linux Mint. All this leads me to conclude that a change was made at some point that either breaks ssh, or else it requires additional setup that the documentation (https://www.system-rescue.org/manual/Network_configuration_and_programs/) doesn't mention.