trouble with ip address

This forum is for admins who are looking to build or expand their OpenVPN setup.
Forum rules
Please use the [oconf] BB tag for openvpn Configurations. See viewtopic.php?f=30&t=21589 for an example.
Post Reply
vooteleaer
OpenVpn Newbie
Posts: 2
Joined: Fri Jan 12, 2018 11:16 pm

trouble with ip address

Post by vooteleaer » Fri Jan 12, 2018 11:31 pm

Hello
This is my first post here, so be gentle with me :D
The situation is as follows:
Ubuntu 16.x running openvpn server. tun0 device bridged with eth0 to br0, 192.168.1.x address space shared with local network.
Several clients connecting via tun0. Let's say some windows machines, some macs. All of those are OK. They get their 192.168.1.x free address and so on.
Except one raspberry, which is the key ingredient in this project.
It uses 4G dongle which acts as eth0, has address 192.168.8.100 in raspbian, also tap0 with normal 192.168.1.x address assigned by server.
So far, so good, except - raspberry has to connect my custom server application, which also has to talk back to raspberry. This application sees raspberry as 192.168.8.100 somehow. Obviously it tries to send stuff back to this address, which of course doesn't exist in VPN.

How on hell the other adapter's IP address gets through vpn?
Last edited by vooteleaer on Sat Jan 13, 2018 12:02 am, edited 1 time in total.

vooteleaer
OpenVpn Newbie
Posts: 2
Joined: Fri Jan 12, 2018 11:16 pm

Re: trouble with ip address

Post by vooteleaer » Sat Jan 13, 2018 12:00 am

tcpdump indeed shows udp packets from 192.168.8.100
01:48:19.791704 IP 192.168.8.100.34227 > 192.168.1.2.14550: UDP, length 36
01:48:19.791771 IP 192.168.8.100.34227 > 192.168.1.2.14550: UDP, length 48
01:48:19.791822 IP 192.168.8.100.34227 > 192.168.1.2.14550: UDP, length 28

and so on

User avatar
TinCanTech
OpenVPN Protagonist
Posts: 5114
Joined: Fri Jun 03, 2016 1:17 pm

Re: trouble with ip address

Post by TinCanTech » Sat Jan 13, 2018 2:01 am

In what way is this related to openvpn ?

Post Reply