OpenVPN strip default gateway in DHCP response

dreif34

Hi,

I have a problem with openvpn stripping down default gateway from DHCP response. I found several post related to this where use of "push xxx" is the solution but it does not apply to my setup.

I try to bind VM (VirtualBox) to a remote network using "server-bridge" setup. The VPN server act a a 'transparent' (layer 2) tunnel. The VPN Client is stzarted on the HOST computer. The DHCP client run in the GUEST VM. The DHCP server is an existing one (not openvpn)

So any 'push' instruction would act on the HOST which do not need it. The DHCP client in the GUEST VM does not get any default router.

I used tcpdump on each NIC and I can copnfirm that "Default-Gateway Option 3" is set in the DHCP response on the VPN server interface but no more in the DHCP response that the VM get.

How may I force openvpn server to not mess with the dhcp request/response?

Thank you in advance for your support,

Regards

Frederic

maikcat

please post your configs

Michael.

dreif34

maikcat wroteplease post your configs

Michael.

port 1194
proto udp
dev tap0
ca   /etc/openvpn/ca.crt
cert /etc/openvpn/server.crt
key  /etc/openvpn/server.key
dh   /etc/openvpn/dh2048.pem
crl-verify /etc/openvpn/crl.pem
server-bridge
client-to-client
keepalive 10 120
comp-lzo
persist-key
persist-tun
verb 3
log /tmp/openvpn-tcp.log

and

client
dev tap4vm
proto udp
remote x.x.x.x 1194
resolv-retry infinite
nobind
pkcs12 client.p12
askpass client.pwd
persist-key
persist-tun
comp-lzo
remote-cert-tls server
verb 3

maikcat

please add this to your server config

push "route 0.0.0.0 255.255.255.255 net_gateway"

Michael.

dreif34

maikcat wroteplease add this to your server config

push "route 0.0.0.0 255.255.255.255 net_gateway"

Michael.

The default gateway is still stripped-off the DHCP answer.

Moreover, I get an error in vpn log (on the host not in VM!)

OpenVPN ROUTE: net_gateway undefined -- unable to get default gateway from system
OpenVPN ROUTE: failed to parse/resolve route for host/network: 0.0.0.0

dreif34

ok. I found it by myself.

server-bridge nogw

from doc : The optional nogw flag (advanced) indicates that gateway information should not be pushed to the client.

It was really frustrating to see this DHCP repsonse being fixed without being told.

Thank you for your support.

Regards

Frederic