Network backup 

Local Area Networks (LAN), refers to the grouping of computers and other devices such as printers, for the main goals of either sharing files, printers or an Internet connection.

A LAN can be connected in many ways including hard wired ethernet cables, a wireless connection, a combination of both, or many other methods. 

LANs can be made up of thousands of computers, or simply consist of two computers that are wired together. A LAN only works in a small geographic area and at most in the same office building or complex. 

Larger, geographically spread networks are called Wide Area Networks or WANs for short.  LANs can be connected together via VPNs. 

A Wide Area Network (WAN), is a large geographically dispersed network.  Unlike LANs, WANs are not restricted to an office or building and can potentially be spread across the globe.  In fact, the Internet itself is a WAN.

WANs are commonly used to link LANs together in larger networks such as Metropolitan-Area Networks, MANs, which are networks put together to offer wireless Internet access across a community or city.

WANs are also used by companies with remote locations.  Utilizing WANs with VPNs (‘virtual private networks’) allow the companies to securely share encrypted data between locations enabling the revolution of mobile workers.

The answer is most definitely.  A Virtual Private Network (VPN) allows you to securely access your network remotely as if you were sitting right in your office.  VPN's are great for the business traveler that is often out of the office and needs to access or copy files while away. 

VPNs used to be strictly used by large companies who used leased lines or dial-up for secure access to their networks; however, VPNs are now just as common for small to medium sized businesses.

For your information: To setup VPN access, you will need a server with 2 network cards.

A Network Attached Storage (NAS) is a dedicated storage device that connects directly to a server and becomes available through a LAN connection rather than being limited to being accessed through one computer. This allows many users to access the storage device at the same time, generally via its own IP.

NAS devices are very similar to file servers but are generally easier to administer.  NAS devices usually have some sort of a control panel to administer the device and access advanced settings.

A Storage Area Network (SAN) is an architecture to attach storage devices (e.g. disk arrays, tape libraries) to servers.  The storage devices would appear to users of the network as local drives.

In contrast to network attached storage (NAS), SAN's will appear as a local device, and NAS' will appear clearly as if they are attached to the network (i.e. accessible via a UNC path or mapped drive).

SAN's are mostly found in large scale operations that have the need to protect multiple gigabytes and even petabytes of data.  SAN's are not very common in comparison to NAS'.

There are several ways to backup data remotely. The most popular method in this day and age is backing up offsite via an Internet connection to an offsite backup provider for a monthly fee.  Backing up offsite is predicted to soon overcome backing up to DVD/CD which requires human intervention to manually store the backup in a secure offsite location.  

Another less popular method of backing up offsite is backing up via a Virtual Private Network (VPN).  A VPN allows a user to backup data to a remote workstation or server through a secure, encrypted tunnel.  Setting up a VPN is usually done by an IT technician as it requires a higher level of technological knowledge than simply using an offsite backup service.