[CentOS] OpenVPN problem

[Marko Vojinovic]

On Sun, 09 Feb 2014 19:33:49 +0000
Timothy Murphy <gayleard at eircom.net> wrote:
> I have OpenVPN set up; I found the brief instructions 
> that come with CentOS openvpn (eg /etc/openvpn/2.0/README)
> perfectly adequate - what I'm asking about is the _use_ of OpenVPN.

Sorry, what exactly are you asking for here? The implemented OpenVPN
is nothing but a (virtual, distributed, etc...) LAN. Imagine several
hosts connected together with a switch and a bunch of ethernet cables.
It is used in the same way an ordinary LAN can be used.

Imagine having several computers connected in a local network. How do
you "use" this LAN? Well, you can ssh/ftp/ping among hosts, you can
deploy various services among them (dns, nfs, samba, apache, mta,
gaming servers, whatever...), and so on. The network is *virtual* in the
sense that there are no physical cables and switches connecting the
nodes directly. It is *private* because all communication is encrypted.
But other than that, a VPN is simply a *network*, like any other
network, and can be used in all the ways an ordinary network can.

An additional usage point is managing access certificates --- if
you share your VPN with other people, you can issue certificates to all
people who are supposed to join the network, revoke certificates from
people you want to kick out of the network, etc.

One obvious benefit of VPN is that the nodes can be widely distributed
geographically, while still connected into a single (virtual) LAN. It
is also completely immaterial how is any given node physically
connected to the Internet --- VPN is transparent to firewalls, NAT-s,
etc.

HTH, :-)
Marko