Hamachi p2p vpn

A few days back I was at grc to run a “shields up” scan on a clients machine and found reference to their Security Now podcast (Leo Laporte and Steve Gibson.) The cast was about a VPN tool called Hamachi… so I revisited and gave a read to the Security Now! transcript. And then visited the Hamachi site. I’ve got to say, I’m impressed on a couple of levels with Hamachi. 1st it sounds as though they’ve done a great approach to a secure free VPN implementation. (Steve Gibson is a pretty good reference….) It’s also easy to install and use and beyond that there are linux/Windows versions of the client currently, Mac will be released after the 1.0 for Linux and Windows.

There are some things that Hamachi does very well and some things that you would be best off looking at openvpn or another VPN approach for. Here’s what it’s great at though, a quick, easy ad-hoc zero-config peer 2 peer (p2p) secure VPN. For starters I installed it on a couple of my linux systems (ok – all 3). The idea is this, when you install hamachi and initialize it, you get assigned a 5.*.*.* network address for your “hamachi” (or ham0) adapter. (Basically tun). 5. addresses technically don’t exist, so by doing this it’s guarantied not to conflict with other networking setups. (However, only 16 million or so machines can use it?)

After initializing you create a network and assign it a password (or join another network with a password.) As you add machines to the network, the central server is contacted by each machine and then it is able to tell each client how to contact the others, so the server does the handshaking (authenticated by a public key from each client.) After that the clients contact each other (no traffic should be passing through the hamachi server at this point.) All with strong encryption. When you stop and re-start hamachi it remembers it’s last state, so if you’re on a public machine make sure to LEAVE network, then it would have to ask for authentication next go around.

The interesting thing is it’s ability to do NAT traversal. They say that the server is actually able to negotiate connections 97% of the time (no pinhole forwards, no firewall adjustments.) Which is pretty impressive. I did actually find a 3% situation once I branched outside of my own (firewalled) network. The next host I added to my network was behind a router and additional firewall (two hops to get to the outside world.) This one failed to find any of the others. The next test after that was a machine with just a software firewall (windows machine) and discovery between that and the “behind the firewall” machines on my network was fairly quick and reliable.

For a situation where you want to specifically connect to a few specific machines and have a secure connection to those machines, this might just be the way to do it. One nice thing that I see is that for instance, with my laptop, I have NO configuration changes to make when it’s mobile, the server deals with all the nasty “figure out where I am” stuff. From what I can see the VPN client is BSD licensed. The biggest disadvantage I see is that it’s a machine to machine connection, not a machine to network connection like openvpn could support. I know I’ve only scratched the surface in covering what it does…. But if you’re looking for a free and easy secure VPN implementation this very well could suit your needs.

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