Firewall

So I'm not great with firewalls. I was wondering if using iptables and having correct rules will protect me anymore than having it disabled? I'm only hosting servers on it.

If so, could I possibly have some help with the firewall part? My idea was allowing port 25565 on the server open for users to connect to my server and the other machines only allow connections to and from that main server. Would this help AT ALL or is it completely unnecessary?

Yes it will help ALOT! but you can also use "ufw"
contact me for more details on skype: Creeper-Help
or email creepershelp1@gmail.com with a subject of "IPTables - Spigot"

A firewall typically helps nearly everything. I employ a firewalls on nearly every single server I use, unless I have a reason for not doing it. I would suggest setting one up just for security - however don't forget to allow connections to SSH and necessary things like that.

It will help minimally and isn't just an unnecessary addition, and if you've never used firewall/iptables before, its worth the experience regardless. I would suggest doing it.

Right well. How would I go about doing this scenario:

My idea was allowing port 25565 on the server open for users to connect to my server and the other machines only allow connections to and from that main server.

Does it provide any additional security at all? I'm going to be limiting SSH access to specific IPs, apart from that will using a firewall and correctly setting that idea up help in any way?

Well it is a GREAT idea to allow only the ports you NEED so no one can easily hack you using other ports that are not "closed" and you restrict ips of accessing those ports and nothing can easily get to you. So yes fire walls can (setup correctly) provide ALOT of protection.

So I'd be perfectly fine without a firewall and the same about of security, more or less? I'm only hosting servers.