I've tried searching the forums and Google, and the only answer I can find is to add the line
However, when I do this, I get the following error
Anyone have any suggestions as to how I can resolve this problem? Thanks for the help.

EDIT: Forgot to mention that I get the error whenever I try to use ssh to connect to another machine.

Instead of putting that line, don't put it and root shouldn't be allowed to login

EDIT: I explained wrong, root is not allowed to login unless you put the line PermitRootLogin yes

It wasn't there to begin with, and root was still able to log on.

Sorry you're right, I remembered wrong, any way, you should put PermitRootLogin no in sshd_config not ssh_config and hopefully it will work (after restarting sshd)

Yeah so I'm stupid and haven't noticed that all the things I've read have said sshd_config and not just ssh_config. Thanks for clarifying that for me.

One more thing. Is it possible for me to stop certian IP addresses from connecting via ssh? Would I have to put something in my iptables script to drop all connections from that ip address? Or is there another way to do this? Thanks for the help.

Add the IP to your /etc/hosts.deny file.

Enjoy!
--- Cerbere

It has been recommended by brains bigger than mine that you should have "ALL:ALL" in you /etc/hosts.deny folder and then specify access from there. I remote administrated my home web-server this summer and found that setup to be quite the pain however all I had to do is check the logs for all the script-kiddies that were turned away to realize the value of my actions.

TomaCzar that approach is perfect but it works only when you have a known group of users with a specific address, it won't do it if you really don't know who is going to access your machine.
I'm running a machine to hold my web site, testing software, etc. I always see some scans on the logs, but I just ignore them (mostly..); I couldn't do what you said because I really don't know who is going to access it (I guess I'm the only one but I've hope)

gbonvehi,

I think there's a happy medium here not being addressed. When you say you should know that I'm doing some of the exact same things. Only certain applications use the 'host.allow, host.deny' or maybe it should more appropriately be stated that certainly applications do not use those files for authentication. Specifically, Apache has its own access roster that can be configured to allow and deny access to its services.
Now I don't know what FTP you use however the two I've used (proftp=past, vsftp=present) require an addition to hosts.allow along the lines of the following

Now that simply allows access to the service, further configuration is needed to allow specific login accounts (or general access if absolutely necessary)
One more comment I'd like to make, if you have an internal network and an external network you can certainly restrict access via that criteria so that services available to the your home/work are not necessarily available to the outside world. a simple
will allow access to all services for anyone on your internal LAN (also anyone who's hacked into your internal LAN...) however it will keep you from ripping your hair out in frustration when machines on a 'trusted' network are told no.
There's always a trade off between security and capability but it's very rarely all or nothing. If you'd like to seriously address security issues you may wish to research a little more at what options are available.