OT: strange network problem

[Ohad Levy]

On Tue, Jan 11, 2022 at 11:26 AM Erez D <erez0001 at gmail.com> wrote:

>
>
> On Tue, Jan 11, 2022 at 9:29 AM Ohad Levy <ohadlevy at gmail.com> wrote:
>
>>
>>
>> On Tue, Jan 11, 2022 at 9:19 AM Erez D <erez0001 at gmail.com> wrote:
>>
>>> The windows 169.25. ip is from APIPA and not from any DHCP server
>>> (ipconfig does not specify a dhcp server).
>>> to be on the safe side I verified udp port 67 is unused on my mac (via
>>> netstat, fuser and socat)
>>>
>>> what boggles me is why can't the window machine access the router and
>>> get an ip when the mac is sleeping
>>>
>>> as the AP switch is layer 2, i would susspect the switch disables the
>>> windows machin for some reason,
>>> e.g. it sees the same mac address from another port or detects abuse of
>>> somewhat from the windows eth port
>>> however i do not understand how is this related to the mac sleeping
>>>
>>> I thought the AP switch maybe defective but puting another GB switch
>>> instead causes the same results ...
>>>
>>
>> can you run tcpdump on your router? does it show the dhcp requests from
>> your windows machine?
>>
> Alas, No. I know it is sacrilege but I use a hot cable modem/router.
> I do not have hardware that can support 500Mb to be used as a linux
> firewall ...
>
openwrt :)

but technically, if you have a 3rd machine, you should be able to see dhcp
requests being broadcasted on layer2

>
> Thanks,
> Erez.
>
>
>>> why do you thing HOMEGROUP is related ? it is a higher layer protocol
>>> when the problems seems to me on layer 2
>>>
>>> Thanks,
>>> Erez
>>>
>>>
>>>
>>>
>>> On Tue, Jan 11, 2022 at 8:36 AM <borissh1983 at gmail.com> wrote:
>>>
>>>> On Monday, 10 January 2022 19:30:55 IST Erez D wrote:
>>>> > I've encountered a network problem
>>>> >
>>>> > i have a mac and a win10 machine connected to a 4 port Gbit wifi6 AP
>>>> > (switch mode).
>>>> > a third eth from the AP goes to the router which is also a DHCP server
>>>> >
>>>> > everything works well until the mac goes to sleep.
>>>> > when the mac goes to sleep, the win10 machine looses it's ip address
>>>> > which becomes a 169. address
>>>> >
>>>> > as soon as i wake the mac up, the win machine regain a valid 10.0.0.x
>>>> ip
>>>> >
>>>> > i tried to replace the AP with a 4 port switch and got same results
>>>> >
>>>> >
>>>> > any idea ?
>>>> >
>>>>
>>>> IP in the  169.254.0.0/16 range is related to bonjour protocol , it is
>>>> a link local communication.
>>>>
>>>> your windows would move to a bonjur ip in many cases but most common
>>>> that can happen if your machine has a bonjour service enabled and an
>>>> Ethernet card with dhcp that can not get an ip from the router.
>>>>
>>>> 1. Check if when the mac is running your windows machine got it's ip
>>>> from the mac and not from the router. in some cases mac can have dhcpd
>>>> running on it, if that is the case you should disable it if you do not need
>>>> it.
>>>> 2. Check if homegroup is enabled on win10, if it is disable it (by
>>>> version 1803 it is no longer active by default, but you could have hacked
>>>> to enable it).
>>>>
>>>>
>>>> _______________________________________________
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>>>
>>
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