So, after going through the tutorial, I feel compelled to share how I got to the end and was able to mount, and then access the metasploitable server.
On my mac, I noticed that many things could not be done the way it was said in the tutorial video, either because Macs can't do it, I didn't have true root access to my machine (unlike the narrator and his fancy Kali Linux), or changes to the server that prevented my attempts. Here is the line of commands that got me access to the server (and an explanation of each).
(I'm assuming that you have already downloaded and installed
nmap on your mac)
$ sudo nmap -sS 10.195.2.2 ;; This gets you the about info about the available services on the network
$ rpcinfo -p 10.195.2.2 ;; again, this gives you the above info about the server.
$ showmount -e 10.195.2.2 ;; this does just as expected
$ sudo mount -o resvport -t nfs 10.195.2.2:/ /tmp/nfs/ ;; the -resvport is needed on my mac because... it worked! I'm not sure why...
This will get you to where I was above.
ASIDE: sorry for the many replies, but I didn't want my comments to get lost in the clutter of the forums.
Once you have the server mounted, now comes the part that differs drastically from the tutorial. You still need to generate an RSA key using
rss-keygen. Then, instead of piping the output of
cat into the servers authorized keys file, first copy the contents of you public key using
cat .ssh/id_ras.pub and then select and copy the output (I'm sure there is a terminal command, but this is just as good for me). Now, open the authorized keys file with admin privileges in nano (or VIM or EMACS... weirdos) using
sudo nano /tmp/nfs/root/.ssh/authorized_keys. Once the file is open copy the contents of your rss public key and then use
ctr-x to exit; type
y to save. If you did everything correct, then you have added your RSA key to the list of authorized keys for the server (WOOT!).
Finally, unmount he server using
sudo umount /tmp/nfs/ and then ssh into the server and have fun.
I hope this helps some of you other Mac users finish this tutorial.