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Some Questions From A Beginner

Hello all!

I just joined here and I am new to using a VPN although I've known about them for a while. I have some questions I'm hoping someone might be able to answer.

1. If a connection is running through my VPN and the VPN dies and the connection continues running through my open internet connection, when I restart the VPN, does the connection automatically start getting tunneled back through the VPN or do I need to stop the connection and restart it to get it going through the VPN again?

2. Why is it that the VPN can only run as fast as your ISP's upload speed limit? (The VPN service has "unlimited" bandwidth. I run at 3Mbits max.)

3. If I have the VPN running globally through tunnelblick and I also have an application running that is making a connection through the VPN as set up in the applications preferences/settings, what happens?

That's all I can think of for now. Thanks in advance for any help!



I'll take a shot at it (since no one else is).

1. In most instances, the use of the VPN is controlled at the OS level, specifically the network stack. If the VPN is up, and your VPN client is configured to use it as the default gateway, it will be used. If the VPN dies, the OS will continue on without it. And if/when the VPN is re-established, it will use it again. It’s just how the network stack works.

2. When ppl make that statement, they’re assuming that you will be using your own VPN server at home to secure your open WiFi sessions. And in that case, yes, your download speeds are limited to your home network’s upload speeds. But if you’re connecting from the home or office to some internet-based VPN server (StrongVPN, HMA, etc.), then of course this doesn’t apply. You should receive whatever speeds are promised by the VPN provider.

3. I have zero familiarity w/ the Mac or tunnelblick, but again, usually VPN access is controlled at the OS level via the network stack. So it tends to affect either every app, or none. You don’t usually configure a VPN client on a per app basis (if that’s what you’re driving at).


Thanks for the reply! I appreciate it. I was a little surprised I didn't get any other responses because the overall "replies/reads" ratio for topics here looked pretty good. Oh well.

As to the questions:

1. Got it. Thank you.

2. Hmm, well that's not good then. I normally get about 20Mbits down and 3Mbits up with my ISP. But with my VPN running (BTGuard) I get 3Mbits down max and the same up. I had read somewhere about someone complaining that due to the nature of VPNs, they can only go as fast as their upload speed. I guess that was referring to going through your home computer from an open wifi. BTGuard advertises unlimited bandwidth so I guess I'm not getting what's advertised.

3. Okay, I could have sworn that I read in a few places that people had configured uTorrent (BitTorrent application) to run through their VPN. I haven't tried since I can accomplish the same goal with the VPN running globally, but I've seen in the settings for uTorrent a section for putting in proxy info. I know a proxy is different from a VPN, but one of the posts I read was from someone who had allegedly configured uTorrent to only run through their VPN.

Well thanks again for the reply.


reply to steiney
VPN is such a generic term that it's hard to pin down exactly what someone means when they use it. It could be PPTP or OpenVPN to one person, perhaps the TOR network to another, or even SSH to someone else. They're ALL "private networks". So it always helps when ppl refer to specific types of VPNs, products, and intended usage.

Again, your typical VPN (as in PPTP, OpenVPN, etc.) tends to “take over” the network stack. It’s one of the safeguards employed by third party VPN clients who want to FORCE all network traffic over their own network for security purposes. In fact, a common complaint from ppl who have to use one for work purposes is that they can’t use their own gateway at home for personal use while the VPN is active!

Now let’s consider BTGuard specifically. If you follow the “how it works” link on their website, you’ll notice it’s using the embedded PPTP client on Windows. So this is another example of the VPN taking over the network stack. They probably configure it as your default gateway (iirc, that’s the default, although it could be changed to not be the gateway, which would defeat the purpose) so that everything you do while connected to the VPN is forced over their own network.

The BitTorrent Proxy is different. In this case, they probably don’t configure a Windows PPTP VPN on your system and somehow make it use that VPN connection, but more likely simply update the BitTorrent proxy settings (IP address and port) to point back to their remote system. And that’s probably either a socks5 or https proxy. It’s easy enough to check. Once the app is installed, go to Options->Preferences->Connection and see what it says for Proxy Server. It probably even has the Authentication field filled out. Just another example of how loosely the term VPN is used.

As far as “unlimited bandwidth”, there’s no such thing. There’s ALWAYS a limit since the resource itself is finite and shared. But obviously some VPN providers will be better in this regard than others. And in the case of BTGuard, you’re also limited by the bandwidth available over the TOR network, which they (BTGuard) can’t control anyway.

So the only way BitTorrent is going to use a PPTP VPN configured on Windows is if either the PPTP VPN is configured as the default gateway (and therefore, like every other app, will use it for IP addresses outside the local network), OR, they’re using some other application that’s connecting to the VPN (either local or remote) and which establishes a local proxy to bridge the BitTorrent app and that VPN. IOW, you can’t make a direct link between the PPTP VPN and BitTorrent client since the latter doesn’t have any other option but to use a proxy. That proxy is always the middleman for secure/private connections. And your typical PPTP or OpenVPN VPN doesn’t provide a proxy of its own. Interestingly, something like SSH does, which is another topic entirely.

Sarcastic Llama? Naw, Just Acerbic
Dartmouth, NS
reply to steiney
When your VPN tunnel goes down, you get an email from langley informing you that your traffic is now open to the general public and that they no longer hold any liability for its inadvertent release.

reply to steiney
Just an addenum to point 2 : what is the weakest link in the entire connection? As eibgrad See Profile says, there's
the limit of the pipe size you're traversing. There can also be a limitation of the equipment doing the en/decryption
which can also contribute.