How can I set up an offline network and simulate VOIP/email?

August 10, 2014 7:19 AM

Help me simulate the internet, without the internet!

Hi, this is a small project that my friends and I are doing for educational purposes - trying to set up a small simulation of email/voice/video technology without an internet connection.

Specifically, we are trying to:

- Create an offline network of 3-6 laptops or tablets, connected by usb or ethernet, using a hub or something similar.

- Have those devices send each other emails (or reasonable simulations thereof) and call each other using something like Skype (voice as a minimum, video would be a bonus), in order to simulate internet-based telecommunications.

I've been researching various software solutions (Mumble/Murmur, Ventrilo, TeamSpeak, etc.) which offer LAN-based comm capability, but it all gets quite complicated quickly, and I'm far from an expert on networking.

I'm wondering if I'm missing some simple solution. Any help would be appreciated!

posted by jet_manifesto to Computers & Internet (2 answers total)

So normally if you were just simulating this, you would not have physical laptops/tablets, but rather run a bunch of virtualized systems on a single host. The computational demands of sending/receiving email and making a Skype call are not that high, so you just get one decent machine with extra memory to boot 3-6 images, and then you don't even have to worry about networking. Run another image as the email server. It just makes everything much easier when you can boot everything from the same image and manage them all from one place. Unfortunately Skype and FaceTime don't work without an Internet connection, so I think you're stuck finding some more specialized software for that.
posted by wnissen at 8:09 AM on August 10, 2014

Best answer: So you need someone who understands TCP/IP networking to the point that you can set up something to do DNS resolving. On my home network, set up so that I can easily detach from the Internet at large, I run dnsmasq on my server, which both assigns DHCP addresses, and lets me give the machines names.

Smarter off-the-shelf routers may allow you to do something similar, if your machines are all broadcasting reasonable names, there's a good chance that a basic router will be able to give them both DHCP addresses (what it normally does), and intercept DNS requests to give them names.

Then you need to set up email. Emails servers can be a royal PITA, but my guess is that any dumb Linux server will happily do local email just fine. So you just set up user accounts, use SMTP and IMAP or POP clients like you normally would on a local machine, and mail gets sent through said server. *Probably*, if your DNS resolving is set up reasonably, don't need to do anything but answer the default prompts.

For video and voice conferencing... uh... If you're cheap, it looks you can set up vlc to do this, but bringing up the connections is a little wonky and it's kind of like "okay, set up a server on machine A to stream video and voice out, subscribe to that on machine B, do the same thing on B and subscribe on A".

I don't have any experience with it, but I'd guess that Ekiga does pretty close to what you want.

I'd be tempted to see about buying a Teamspeak server license to run on a machine in-house.

The big thing here is that in the grander Internet world, there are a bunch of servers out there that you'll need to replicate. The biggie is DNS, which, as I mentioned, a good DHCP server solution will solve for you. After that it's just putting up services on a local server that the other machines can talk to.
posted by straw at 11:06 AM on August 10, 2014