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Starting VPN with bind to IP prevents all external traffic!

Posted: Mon Feb 22, 2016 9:46 am
by feratechinc
So I have a server with dual WAN and 2 public IP addresses.

I'm trying to bind OpenVPN to connect to one WAN and leave the other public. However, as soon as I start the OpenVPN service it kills all external traffic and I need to remote into another local server to stop the service and be able to log back in.

The VPN and everything connects and works fine. I just need to leave the other interface alone. I don't understand why starting the service is messing with traffic on both interfaces if it's only bound to one IP.

Server Info:
Debian GNU/Linux 7.9
openmediavault 2.1.28
Linux Kernel 3.2.0-4-amd64

Code: Select all

client
dev tun
proto udp
local XXX.XXX.XXX.XXX
remote XXX.XXX.XXX.XXX 2049
##username and password in file called pass
auth-user-pass pass

resolv-retry infinite
persist-tun
persist-key

ca ca.crt
tls-auth ta.key 1

cipher AES-256-CBC
ns-cert-type server
comp-lzo
verb 3

Re: Starting VPN with bind to IP prevents all external traff

Posted: Mon Feb 22, 2016 12:09 pm
by Traffic
feratechinc wrote:I don't understand why starting the service is messing with traffic on both interfaces
It is not the service .. it is that you are connecting to a server which probably redirects your default gateway.

Re: Starting VPN with bind to IP prevents all external traff

Posted: Mon Feb 22, 2016 1:42 pm
by feratechinc
Isn't the point of binding the interface to prevent this?

Is there any way to have this work?

Re: Starting VPN with bind to IP prevents all external traff

Posted: Mon Feb 22, 2016 2:55 pm
by Traffic
feratechinc wrote:Isn't the point of binding the interface to prevent this?
No.
feratechinc wrote:Is there any way to have this work?
Learn routing ..

Exercise:
  • Terminate ALL VPN connections
  • Post routing table before connection
  • Start VPN client which causes the problem
  • Post routing table after connection