enedil
Posts: 80
Joined: Sat Feb 21, 2015 4:22 pm
Location: Toruń, Poland
Contact: Website

Cannot ping

Mon Oct 12, 2020 12:04 am

I had a problem, that my home wifi router is situated just on the other end of my house than my desk and connectivity is really low. However I really wouldn't like to have a long cable that goes through whole house, and thus I thought that I might put my RPi 4 in my room (on the other end, where the signal is still quite strong), and from there connect my laptop with RPi with cable.

Now come the problems. The RPi is connected to wifi (wlan0 interface). I connected laptop and RPi by cable. I'm using Raspberry Pi OS and it automagically setup an IPv4 address (169.254.72.25/16). On my laptop, I'm using Fedora and use NetworkManager for connectivity. I tapped on wired connection settings, added static IP 169.254.72.26/16 with gateway 169.254.72.25. After these manipulations, I can ping my rpi through cable (ping 169.254.72.25 works). However, if I try ping 192.168.0.13 (this is the ip addr of rpi on wlan0), I never get responses. My local wifi network is 192.168.0.0/24.

Routes on both devices:

Code: Select all

~ $ route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         169.254.72.25   0.0.0.0         UG    20100  0        0 enp0s20u1
169.254.0.0     0.0.0.0         255.255.0.0     U     100    0        0 enp0s20u1

RPi:

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pi@raspberrypi ~> /sbin/route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         192.168.0.1     0.0.0.0         UG    303    0        0 wlan0
169.254.0.0     0.0.0.0         255.255.0.0     U     202    0        0 eth0
192.168.0.0     0.0.0.0         255.255.255.0   U     303    0        0 wlan0
I also checked whether the ping actually reaches the RPi, so I used tcpdump on RPi, and there are lines like

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No	Time		Source	Destination	Protocol	Length	Info
26	1.561827	0.0.0.0	192.168.0.13	ICMP		98	Echo (ping) request  id=0x000f, seq=2/512, ttl=64 (no response found!)
What can be done here?
- What Can a Thoughtful Man Hope for Mankind on Earth, Given the Experience of the Past Million Years?
- Nothing.

Kurt Vonnegut, Cat's Cradle

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DougieLawson
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Re: Cannot ping

Mon Oct 12, 2020 7:44 am

Any language using left-hand whitespace for syntax is ridiculous

Any DMs sent on Twitter will be answered next month.
Fake doctors - are all on my foes list.

Any requirement to use a crystal ball or mind reading will result in me ignoring your question.

enedil
Posts: 80
Joined: Sat Feb 21, 2015 4:22 pm
Location: Toruń, Poland
Contact: Website

Re: Cannot ping

Mon Oct 12, 2020 11:12 am

That's a good suggestion, but I would anyway like to discover what was the problem in the aforementioned setup. This has to have something to do with RPi, as packages reach it, but it doesn't respond.
- What Can a Thoughtful Man Hope for Mankind on Earth, Given the Experience of the Past Million Years?
- Nothing.

Kurt Vonnegut, Cat's Cradle

User avatar
RamaSpaceShip
Posts: 156
Joined: Sun Apr 26, 2020 12:19 pm

Re: Cannot ping

Mon Oct 12, 2020 2:54 pm

Get a pair of power line Ethernet devices.
I found them the best solution when Wifi has troubles.

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pi-anazazi
Posts: 937
Joined: Fri Feb 13, 2015 9:22 pm
Location: EU

Re: Cannot ping

Mon Oct 12, 2020 2:59 pm

169.254.72.x = LinK Local, non-routable IP...
Kind regards

anazazi

enedil
Posts: 80
Joined: Sat Feb 21, 2015 4:22 pm
Location: Toruń, Poland
Contact: Website

Re: Cannot ping

Tue Oct 13, 2020 2:15 pm

pi-anazazi wrote:
Mon Oct 12, 2020 2:59 pm
169.254.72.x = LinK Local, non-routable IP...
That was it <3
- What Can a Thoughtful Man Hope for Mankind on Earth, Given the Experience of the Past Million Years?
- Nothing.

Kurt Vonnegut, Cat's Cradle

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