On Thu, Feb 15, 2018 at 2:46 PM, Andy Ruddock <andy.rudd...@rainydayz.org <mailto:andy.rudd...@rainydayz.org>> wrote:

   Todd Andrews wrote:
    > Hi All,
    > I'm running dnsmasq 2.76 on a Raspberry Pi. It's been working
   great for
    > months but today I started seeing an odd behavior for a specific
    > device and I don't know how to troubleshoot it.
    > The device is a Dell Inspiron 5577 Windows 10 Home edition laptop
   with the
    > latest Windows updates. It's getting an IP address of I
    > first noticed the problem when I tried to establish a VNC
   connection to it
    > because I can't connect via its hostname, "sagan", but I can
   connect via
    > its IP address.
    > Neither the IP assignment nor the laptop's MAC address appear in
    > dnsmasq.leases. The only reason I know it is assigned .115 is by
    > going to the laptop and running the Windows 'ipconfig' program at the
    > command prompt.
    > I've rebooted the Raspberry Pi and the Windows 10 laptop, but it
    > made a difference.
    > More info below. Does anyone have any ideas?
    > Regards,
    > Todd

Hi Andy, thanks for getting back to me so quickly. (I originally sent this reply yesterday but forgot there's a maximum size per post to this list. Replaced screen capture with a link below.)

   Are you sure the windows box hasn't been configured with a static IP

I'm positive: click to view screen capture <https://www.dropbox.com/s/cwy72yu4sly62mp/sagan-configured-as-dhcp.PNG?dl=0>

   Any information when you refresh the IP address from within a cmd window
   in Windows?
            ipconfig /renew

I never would have thought to try this. It gave a strange error but renewing fixed the problem immediately. Here's the error:

   C:\Users\taa>ipconfig /renew

   Windows IP Configuration

   An error occurred while renewing interface Ethernet : The name
   specified in the network control block (NCB) is in use on a remote
   The NCB is the data.


Having a specific error allowed me to Google it and find Bizarre DHCP server error solved <https://web.archive.org/web/20161126203756/http://www.formortals.com/bizarre-dhcp-server-error-solved/>. The poster at that link 1) was not getting an IP address at all, 2) was running a Windows DHCP server, and 3) "found a second reservation in DHCP which looked odd; it had the same IP address as the first one that we deleted but it had an entirely different MAC and name."

This made me remember that a couple of weeks ago I changed my laptop's Computer Name in Windows.

Does this mean there is some other place where dnsmasq might have cached the IP address or MAC or hostname? I'm trying to figure out why dnsmasq.leases had no reference to the laptop's IP/MAC/hostname, neither the previous hostname or the new one. Maybe this is one of those cases that is so bizarre it defies explanation (and I can live with that). :D
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