On Tue, 5 Oct 2004, Mathias Sundman wrote:
I'm experimenting with the "Media Status" = Always Connected on the TAP
device (on Windows XP).
When using this, I found --dhcp-renew and --dhcp-release useful, to have
the adapter release and renew the IP when starting/stopping diffrent
openvpn tunnels.
All my configurations work fine with this except for one, where I use a
DHCP server on the remote network, and bridges that to my TAP interface.
This worked fine, when Media Status was set to Application Controlled, and
I did not use dhcp-renew, but now it doesn't. I just don't get any IP
address.
Running ipconfig /renew tap-dev gives me an IP adress though...
Is there perhaps a bug that --dhcp-renew only works with the internal DHCP
server in the TAP driver?
--dhcp-renew is a simple call to the IP helper API. The implementation is
internal to Windows.
You might want to try running the debug version of TAP-Win32:
http://openvpn.sourceforge.net/beta/
This will give you a detailed picture of the operation of the internal
DHCP server.
Another related thing I've always wondered but not asked is:
Does OpenVPN or the TAP driver block DHCP requests from passing the tunnel
when using the internal DHCP server in the TAP driver, or how do we make
sure the internal DHCP server answers the DHCP requests, and not the DHCP
server on the remote bridged network?
The internal DHCP server should take priority over any remote DHCP server
when the adapter is ioctled with TAP_IOCTL_CONFIG_DHCP_MASQ, which is
triggered by --ip-win32 dynamic.