SSH vs VPN vs VNC vs Software vs RDP. Which to choose and why?

[mxmaniac]

I am relatively new to networking. I've set up basic home networks/wifi. But never done anything involving accessing my network externally.

I have just done about 10 hours of general reading about this stuff, but have been having a very tough time trying to figure out just how they compare, or what situations you could choose one versus another.

Theres SSH, VPN, VNC, RDP, software like Teamviewer, Running the device as a server, and probably many more. So what are the pros and cons? Which ones are generally the favorites and least favorites, and why?

A couple more specific questions.
1. SSH vs VPN. As I understand SSH is like a direct terminal directly to a port, and VPN is much more broad with more options, both are encrypted. So why would anyone even choose SSH anymore? Isn't that like using ms dos when windows is available?
2. Teamviewer vs other. Haven't used teamviewer but it sounds awesome, being cross platform, appraently you can use linux from windows, or windows from android, etc and no port forwarding or advanced router setup needs to be setup, it supposedly just works, and is supposedly highly encrypted. So what's the downside? Just that it requires the software, or is a lot of other downsides which would make the other choices better?
3. If a computer is simply referred to as a "server", which type of service or protocol is it generally using, or are there all different types of servers? Like it can be a vpn server or http server? Can they ever be both? Is a computer with a single port open for SSH considered a server? I'm sure I'm not exactly wording this well, but its obviously I'm a little confused on just what defines a computer as a "server" vs say a desktop which can be accessed remotely.

Thanks.

 

[Mushkins]

1.) SSH and a VPN are two very different things. SSH is a protocol for encrypted console/terminal communications. I use SSH to log into my switches and edit the configurations. A VPN is a persistent secure tunnel used to logically bridge two networks. I have a point to point VPN configured between two routers in two offices to facilitate connectivity between two physical networks that are *one* logical network (in this case a single domain). The devices handle the secure communication and routing, the workstations on each end act as if they're physically sitting in the same office and can securely access internal resources regardless of which office the physical servers/printers/whatever are in.

2.) Software like teamviewer/logmein/etc are remote access applications. It's an alternative to RDP, and most of them are VNC based. You install the server software on a PC, then use the client software to connect. They typically do a good job of punching through NAT so you dont need to play around with port forwarding and firewall settings, but they also have a tendency to be slow/unresponsive and depending on which one you're using you're limited by the features of the software. For example, with logmein you need to pay for a premium subscription to share printers and transfer files between your local machine and the host machine. Hands down, nothing beats Windows baked-in RDP for remote access, but it obviously doesnt work with linux/osx and for a business you're talking a terminal services server with expensive licensing if you want to use it to log in from an external PC.

3.) A server is honestly a pretty vague term. It's really just a PC with a specific software configuration, whether thats a server OS (Windows Server 2012), or running a particular centralized server application (ex. Microsoft Exchange) that client software would connect to. Dedicated server hardware typically uses higher quality hardware, specialized cases, and runs a hardware RAID to help account for hard drive failures and minimize potential downtime, but there's no reason you cant put server software on a regular consumer-grade PC. I built an i3 rig as my home media server and put Server 2012 on it, and run all my server software on it. How you access it doesnt have anything to do with whether or not its a server, you just hear a lot about remote access with servers because they're typically sitting in a locked closet somewhere with no mouse/keyboard/monitor connected to them. Physically going to each server to administer them would be a nightmare, so IT techs just remotely log in to them from their desk instead. http://en.wikipedia.org/wiki/Server_(computing) does a pretty good job of explaining the fundamental differences between a regular old PC and a server.

 

[Savatar]

A similar question, depending on your use-case, is asked here: http://forums.anandtech.com/showthread.php?t=2357848

I thought this might help to give some possibilities on how to connect to a remote system via something like RDP/VNC.