How do I remotely access my Snow Leopard server from my Mountain Lion MacBook Air

Question

Does anyone know of an idiot's guide to setting up a VPN to access my server? I'm running Snow Leopard server in the office and I'd like to be able to access the server, probably just from one computer (MacBook Air runnung Mountain Lion) from home.
I'm not sure if it complicates things or not, but the office is in an area with poor broadband and so the internet connection is via satellite broadband. The set up is a satellite modem into a Gigabit router and the server is connected to the router via an unmanaged switch.
As an aside, I'm considering changing this set up so that the modem plugs into a Time Capsule and the server will connect directly into the TC. The desktops will then run into the server via the unmanaged switch or wirelessly via TC - any thoughts on the best set up here? Are cables into a switch better/worse than using TC's wireless facility.
Is this something that I, as a reasonably competent computer operator but definitely not an IT expert, could do, or should I get someone in to set it up for me?
Thanks in advance
Jim

Answer 1

VPNs aren't particularly special or weird or secret or such.  They're "just" a network connection.  A sometimes very fussy network connection, but a network connection.
My preference is to use a firewall that includes an embedded VPN server.  This for several reasons, as it avoids trying to forward the VPN through a device that's using NAT [1], and it means you can connect to multiple devices on the target LAN, and you can connect even if the OS X Server box is down.
Other folks will forward the VPN through NAT, and use the VPN server that's available in various versions of OS X Server.
Forwarding a VPN through NAT does work, but can also sometimes not work.  NAT can cause some types of VPNs to get tossed off when (for instance) there's a second VPN connection arriving.
In various cases everything connects and works the first time, and in other cases it's trial-and-error.
With a VPN-capable firewall (which is a step above your average residential firewall), usually configuring the firewall as a L2TP server or the Cisco protocol, if you want to use the standard OS X or iOS clients.  Or PPTP — which is easier to get working — but less secure.  Once the firewall and the VPN server is set up — and that's where most of the "fun" is — then the set-up in Network Preferences is (usually) pretty simple.
There are thousands of OS X VPN set-up articles around, but the details all hinge on the particular VPN server, and whether you're going to try to push the VPN through (for instance) that Tome Capsule and its NAT.   Until you sort out your VPN target and/or VPN client, and what sort of attacks you're securing against...
As for this case, satellite latency is large.  The latency involved is the time it takes to the command or the text from your local Mac to the satellite ~35,786 kilometers up and then ~35,786 kilometers back down, and then the response back again.  That's about a quarter second, each way, at the speed of light.  Transferring big files is fine (once the connection is open and the transfer gets rolling), but anything interactive — such as a typical use of a VPN — is going to have a noticable lag.
Yes, it'll be easiest to get somebody to work through your requirements and expectations, and initially set this up for you.  Or you can use this as an opportunity to read about and learn more about IP routing and networking and VPNs, too.
[1] VPNs seek to ensure that the network connection is secure, and from a known client IP source address to the IP address of the target VPN server.  NAT explicitly obscures the network connections, and often has multiple client hosts located behind one IP address.   Put another way, the VPN and NAT software implementations are working at cross-purposes.