I have a mobile gateway connected to my VPN via OpenVPN and a 2G connection. Now I observe some unexpected traffic (~20MB / day) and wonder where it comes from. While I'm connected to the gateway I see most traffic flowing to my VPN Server (but that might also be my active connection).

So my question is: what is the average traffic caused by OpenVPN when my gateway is connected to the VPN but not sending data through it?

I do not have redirect-gateway def1 enabled.

To monitor real time traffic I used iftop; for long time monitoring the OpenWRT on my gateway does not have any of these packages available: wrtbwmon, vnstat, YAMon, luci_app_statistics, bandwidthd, ntop

Any hints how to find our where my traffic comes from (IP, Port, Process) in the long term would also help me a lot.

  • Unfortunately, questions about consumer-grade devices are explicitly off-topic here, You could try to ask this question on Super User. – Ron Maupin Nov 11 '18 at 16:57
  • Whats consumer-grade? I'm facing a an Industrial LoRaWAN gateway that we connect using a OpenWRT based industrial GSM Modem. – Tarion Dec 15 '18 at 0:20
  • OpenWRT is off-topic because it runs on consumer-grade devices. What are the network device models? Do the manufacturers offer optional, paid support? – Ron Maupin Dec 15 '18 at 0:22
  • I'm sure they do, you can find the product (running the OpenWRT) here: lorixone.io – Tarion Dec 15 '18 at 9:02
  • The problem is that the manufacturer of OpenWRT does not offer optional, paid support, a requirement here, nor can I find such an offer for the device you linked. – Ron Maupin Dec 15 '18 at 17:26

I've got ~180 KB after one hour with an idle connection - so, depending on the exact OpenVPN version and configuration, 20 MB/day seem about right.

You'll need to monitor the connection on the gateway itself to find out what exactly this traffic is. You should be able to run tcpdump on OpenWRT - however, consumer-grade devices are off-topic here.

  • see comment above – Tarion Dec 15 '18 at 0:19

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