OpenVPN server and client on the same machine (RPi)

horizn · 05-07-2019, 01:57 PM

Hi,
I have RPi running OpenVPN server and client, both in routing. While server is running fine when client is down, it stops working when the client is up. RPi itself has still access to the internet via the client VPN.

Internet
^
|
ISP Router 192.168.1.0/24
^
|
eth0 RPi (192.168.1.17)
- tun0 OpenVPN server(192.168.2.0/24)
\ tun1 OpenVPN client(10.1.0.0/24)

I tried to add:
ip rule add from 192.168.1.17 lookup 10
ip route add default via 192.168.1.1 table 10
but with no luck. Any idea how to fix that?

ferrari · 05-08-2019, 06:40 PM

First thoughts are speculative as you haven't shared enough detail. When the OpenVPN client becomes active, I assume that the remote VPN server may push a 'redirect-gateway' directive to your local OpenVPN client ie this would change the R.Pis default gateway. Now all internet traffic will be via the VPN. That would break any connections to your R.Pi OpenVPN server. Some policy-based routing will be needed to ensure properly route traffic that should go via the VPN tunnel and traffic that should not.

horizn · 05-09-2019, 10:54 AM

Quote:

Originally Posted by ferrari

First thoughts are speculative as you haven't shared enough detail. When the OpenVPN client becomes active, I assume that the remote VPN server may push a 'redirect-gateway' directive to your local OpenVPN client ie this would change the R.Pis default gateway. Now all internet traffic will be via the VPN. That would break any connections to your R.Pi OpenVPN server. Some policy-based routing will be needed to ensure properly route traffic that should go via the VPN tunnel and traffic that should not.

Yes, that correct assumptions, except I can still connect to the server and reach first hop.

horizn · 05-10-2019, 09:59 AM

Quote:

Originally Posted by horizn

Yes, that correct assumptions, except I can still connect to the server and reach first hop.

If I add any rule and then set routing then I can't connect to the VPN server.

ferrari · 05-11-2019, 01:35 AM

See if this helps...
https://forums.openvpn.net/viewtopic.php?t=21535

horizn · 05-11-2019, 12:06 PM

I've seen that before I posted here. It doesn't work for me.

ferrari · 05-12-2019, 04:56 PM

You worte that you tried...

Quote:

I tried to add:

Code:

ip rule add from 192.168.1.17 lookup 10
ip route add default via 192.168.1.1 table 10

Perhaps that should that have been...

Code:

ip rule add from 192.168.1.17 table 10
ip route add default via 192.168.1.1 table 10

horizn · 05-13-2019, 05:03 AM

Quote:

Originally Posted by ferrari

You worte that you tried...

Perhaps that should that have been...

Code:

ip rule add from 192.168.1.17 table 10
ip route add default via 192.168.1.1 table 10

Sorry, I didn't make myself clear enough. I have tried many options including the ones on the openvpn community forum. However I have another idea I'll test this evening.

ferrari · 05-13-2019, 05:55 AM

Great. Let us know how you get on.

horizn · 05-13-2019, 04:33 PM

Quote:

Originally Posted by ferrari

Great. Let us know how you get on. :)

OK, it doesn't work whatever I try.

Code:

ip rule add from 192.168.1.0/24 or 192.168.2.1 or 192.168.1.17 or 192.168.2.0/24 table 10
ip route add default via 192.168.1.1 or 192.168.2.1 or 192.168.1.17 table 10

Code:

cat /etc/iproute2/rt_tables
#
# reserved values
#
255     local
254     main
253     default
0       unspec
#
# local
#
#1      inr.ruhep
10      vpn

ferrari · 05-13-2019, 05:03 PM

It's hard to diagnose from a distance, and I don't have the time to drill deeper with this. You could cast your net wider by posting your issue on the openVPN Forum perhaps.