[kwlug-disc] Networking issue

[John Van Ostrand]

Something with spanning tree protocol, of which I know almost nothing?

On Mon, Aug 5, 2019 at 6:21 PM Khalid Baheyeldin <kb at 2bits.com> wrote:

> No.
> R2 does not provide any power to anything. Nothing plugged in its USB port.
>
> On previous instances of this issue (months back), I was able to make
> things
> work by rebooting both routers, then power cycling the Pi (which I don't
> want
> to do, file system corruptions and all that).
>
> Today, I can't recover. Maybe because I messed with the arp tables?
>
> On Mon, Aug 5, 2019 at 6:18 PM Raymond Chen <raymondchen625 at gmail.com>
> wrote:
>
>> Does your R2 provide power for your Raspberry Pi? I used to have a router
>> behaving strangely when its USB was connected to my Raspberry Pi. I would
>> try unplugging all devices from R2’s USB ports and see if that works.
>>
>> Raymond
>>
>> On Mon, Aug 5, 2019 at 16:50 Khalid Baheyeldin <kb at 2bits.com> wrote:
>>
>>> I have this rare problem that is extremely annoying when it happens.
>>> Basically, I have two routers. R1 is the main home router, connected
>>> to the internet, managing DHCP, and so on. The other router, R2, has
>>> no DHCP, and is simply for range, as well as a couple of RJ45 devices,
>>> due to proximity to those devices.
>>>
>>> Some WiFi devices that report temperature, humidity, ...etc. report
>>> to R2 due to better range. A Raspberry Pi is connected to R2 directly
>>> using RJ45. The Pi and the WiFi devices have static IPs in R1 served
>>> using DHCP.
>>>
>>> On rare occasions, the WiFi on R2 misbehaves. I can still ssh into the
>>> Pi, but the WiFi devices have trouble reporting to the Pi. The solution
>>> is to reboot the routers. Doing so makes WiFi more stable, but then
>>> the Pi is inaccessible over ssh or HTTP. I have to cycle power to the
>>> Pi, and I hate doing that since it may corrupt the file system on the
>>> SD card.
>>>
>>> Even when reboot both routers and cycle power, the Pi is not accessible
>>> still. Pings fail, let alone ssh. Don't know why.
>>>
>>> The only clue I can find is that when I use arp (from R1), the Flags
>>> column for the Pi is 0x0 while it is 0x02 for all other devices.
>>>
>>> I tried to delete the arp entry for the Pi, using this, from a Linux
>>> machine:
>>>
>>> arp -d 192.168.0.x
>>> arp -s 192.168.0.x b8:27:xx
>>>
>>> After that, I see this:
>>>
>>> Address HWtype  HWaddress           Flags Mask            Iface
>>> zz           ether       b8:27:xx                CM
>>>  eth0
>>>
>>> Again, the Flags column is CM, while it is C on other devices.
>>>
>>> How can go about troubleshooting this extremely annoying problem?
>>>
>>> --
>>> Khalid M. Baheyeldin
>>> _______________________________________________
>>> kwlug-disc mailing list
>>> kwlug-disc at kwlug.org
>>> http://kwlug.org/mailman/listinfo/kwlug-disc_kwlug.org
>>>
>>
>
> --
> Khalid M. Baheyeldin
> 2bits.com, Inc.
> Fast Reliable Drupal
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>
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>


-- 
John Van Ostrand
At large on sabbatical
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