Excessive outgoing data usage?

[Can]

Hello Guys,

I am trying to find out what is going on with my tunnelblick & openvpn setup. As soon as I turn on my VPN, I see excessive data usage. It's an outgoing traffic and I feel like something fishy going on.

I've set up fresh openvpn server onto fresh ubuntu box via trusted/default ubuntu repositories.

I configured everything and it's all working properly. (I've done this before) I can connect to VPN and access my internal resources without any problem.

While doing some testings, I noticed that little tunnelblick window shows 16MB/second (about 150mbps) outgoing traffic. My computer is on idle state (I am not uploading anything) and this is very strange.

I've checked my activity monitor right away to confirm that tunnelblick is calculating the traffic correctly and I confirmed that 16MB/s outgoing traffic there as well. When I turn off my VPN, everything is ok. As soon as I fire up tunnel blick and connect my vpn, data usage starts to go crazy.

I've installed nload onto my mac to monitor specific virtual network interfaces. I can see that utun0 (default tunnelblick network interface) using crazy amount of outgoing traffic.

Can you guys suggest me some ways to find out what is going on?

This is very strange.

[Tunnelblick developer]

Wow, that is a lot of data. Tunnelblick itself doesn't send much data (just checks tunnelblick.net for updates when launched and once a day thereafter, and two GET requests to tunnelblick.net each time you connect. That is reflected in the total of 173 bytes sent and 4KB received by Tunnelblick itself. You can inhibit all Tunnelblick network activity on Tunnelblick's "Preferences" panel.

So this is either traffic being generated by OpenVPN or some other program on your system. Because it only happens when the tunnel is connected, it seems most likely that the problem is with OpenVPN (or the OpenVPN configurations on the server and/or client). Is that reflected in Activity Monitor (that is, is a process named "openvpn" using all this outgoing bandwidth and no other programs are using a lot of bandwidth)?

I think you should consult OpenVPN experts:

• OpenVPN FAQ
• OpenVPN HOWTO
• OpenVPN 2.3 Man Page
• OpenVPN Documentation
• OpenVPN Users Forum
• OpenVPN Users Mailing List

It would also be a good idea to look at Tunnelblick's log, and the Console log, for clues.