Hi,
i'm having some troubles setting up a bridged vpn.
First of all, the topology:
Here the VPN server is a trashware machine running Debian Jessie.
Its function is to act as access server to control my networking lab equipment, by forwarding serial ports to telnet.
I set up on it an OpenVPN server, with the intent of connecting virtual machines running on the VPN client through the tunnel directly to the lab equipment, by bridging the ethernet interface on the server (which actually connects to LAN through a wireless usb nic), and bridging virtualbox guests to the tap interface on the openvpn client.
With this setup i obviously want that the virtual machines get their addressing information from a dhcp server located into the lab, not from the openvpn server.
Virtual clients can get ip address, netmask, dns servers etc. correctly, but not default gateway address.
Comparing wireshark captures on both sides of the tunnel i see that openvpn cuts off default router field from DHCP offer packets, as indicated also by logs on client side saying "Extracted DHCP router address: 192.168.1.1" (which is the address of the external dhcp server).
In a "normal" situation this is the expected behaviour, 'cause it would mess up client's routing table, however in my intention this feature is not wanted.
I could set up the openvpn server itself to push default gatweay address, but in a lab environment addressing is continuously changing, and reconfiguring openvpn server every time is not a feasible solution (also, i will sometime have to test dhcp functionality through the tunnel...).
So, how i can disable this feature or eventually find a workaround (maybe through nat rules)?
Here are my configuration files:
server.conf
local {wlan0 ip address}
port 1194
proto udp
dev tap0
dev-type tap
persist-tun
server-bridge
persist-key
dh dh768.pem
ca ca.crt
cert server.crt
key server.key
client-to-client
duplicate-cn
keepalive 30 120
auth none
cipher none
user nobody
group nogroup
status /var/log/openvpn-status.log
log /var/log/openvpn.log
verb 3
mute 20
client.conf
client
remote {server ip address}
port 1194
proto udp
dev tap0
dev-type tap
persist-tun
persist-key
ca ca.crt
cert client.crt
key client.key
keepalive 30 120
auth none
cipher none
daemon
script-security 2
user nobody
group nogroup
up "tap0_up.sh"
verb 3
mute 20
Thank you in advance for your help
