Re: [Openvpn-users] Windows XP SP2 ignoring DHCP offer

[James Y. <ji...@yo...>]

On Fri, 25 Mar 2005, Terry L. Inzauro wrote:

> James Yonan wrote:
> > On Fri, 25 Mar 2005, Martin Wallgren wrote:
> > 
> > 
> >>Hi!
> >> 
> >>I'm running OpenVPN 2.0rc17 on Windows XP Pro with SP2. No third-party
> >>firewalls is installed and the built-in firewall in XP is disabled for the
> >>TAP interface. I'm connecting to a remote server and according to the log a
> >>subnet is allocated (10.8.0.28/30). When using ip-win32 dynamic I can see in
> >>windump and ethereal that Windows sends a DHCP request and 10.8.0.29 sends a
> >>DHCP offer. This is repeated four times.
> >> 
> >>Somehow Windows ignores the DHCP offer and assign an IP in the 169.254.x.x
> >>range.
> >> 
> >>I also tried using ip-win32 manual configuration with 10.8.0.30/30 and the
> >>route is added for 10.8.0.0/24 via 10.8,0.29. When I try to ping the host at
> >>10.8.0.1 only ARP request is transmitted. For every ping an ARP request is
> >>sent asking for MAC of 10.8.0.29 and the reply coming in. Nothing shows up
> >>in the ARP table.
> >> 
> >>It seems like everything sent to the interface is ignored.
> >> 
> >>I tried the same configuration in VMWare and Windows 2000 with success.
> >> 
> >>Any hints on why the packets drop?
> > 
> > 
> > One way to debug DHCP issues with the TAP-Win32 driver is to use the debug 
> > version of the driver.  See this zip file for a debug build of the driver 
> > + instructions.
> > 
> > http://openvpn.net/beta/tapwin32-debug.zip
> > 
> > James
> 
> I am not one to specify a problem as a bug but I am experienceing 
> similar isues except I am seeing them only on machines(win2k server / 
> 2k3)  that act as DHCP servers.
> 
> my workaround for this was to set the ip manually. .....

Remember that if you want automatic IP address assignment via --ip-win32
dynamic, you need to have a DHCP client service running.  This may not be
the case on machines which are acting as DHCP servers.

I'm happy to look at the tapwin32-debug output if you suspect an OpenVPN
bug -- just install the debug driver and remember to set --verb to at
least 7 and don't use --mute.

Having said that, I'm fairly confident that the driver is working 
correctly -- all the cases I've looked at recently have proven to be 
issues with either firewalls or the DHCP client service simply being 
turned off.

James