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Help Antisocial phone on wifi: talks only to my router, not other devices?

Nonny Mouse

Lurker
Oct 16, 2019
4
2
The main devices on my local network are:

* Computer (192.168.1.68)
* Laptop (192.168.1.66)
* Smartphone (Xperia XZ2 Premium / Android 9) (192.168.1.72)

They connect through:

* Router (192.168.1.254)

Everything can ping the router
The router can ping everything
Everything can have net access through the router
The computer and laptop can ping each other (through the router)
.... but for some reason, the computer and laptop can't ping the phone, and vice versa.

I've been boggling over this and have run out of ideas. Nothing is running a firewall (router, computer, laptop, smartphone). Routing tables on both the computer and laptop are nothing special.

Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
default dsldevice.lan 0.0.0.0 UG 600 0 0 wlp0s29u
1u8u1
192.168.1.0 0.0.0.0 255.255.255.0 U 600 0 0 wlp0s29u
1u8u1
192.168.124.0 0.0.0.0 255.255.255.0 U 0 0 0 virbr0

Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
default dsldevice.lan 0.0.0.0 UG 600 0 0 wlp3s0
192.168.1.0 0.0.0.0 255.255.255.0 U 600 0 0 wlp3s0
192.168.122.0 0.0.0.0 255.255.255.0 U 0 0 0 virbr0

The smartphone, as mentioned, shows up fine in the router's interface, and it's built-in ping utility can ping it (and vice versa). There's no special routing parameters that can be configured in the router interface, and it looks no different than any other device on my network.

Any ideas as to what I can do to try to "socialize" my smartphone with my other devices? :)
 
Welcome to Android Forums, Nonny Mouse!
the computer and laptop can't ping the phone, and vice versa.
A little more information would be helpful. When you say they "can't ping" each other, precisely what do you mean? What method are you using to ping them, e.g., the ping command at a command line? What output does it give?

Also, what operating system do you use on your computers?
 
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Welcome to Android Forums, Nonny Mouse!

A little more information would be helpful. When you say they "can't ping" each other, precisely what do you mean? What method are you using to ping them, e.g., the ping command at a command line? What output does it give?

Also, what operating system do you use on your computers?

Thanks so much for responding! :)

To ping from the phone, I've used two different Android ping applications - Ping and Ping Tools. The latter actually does scans of the local network; it only sees itself and the router.
To ping from the router, there's an internal built-in ping utility.
To ping from my computers (both are Linux), I used the standard ping command.

The background is that I hadn't bothered to check up on my phone's backup system (FolderSync) until recently, and I discovered that it apparently hasn't been backing up to my computer since last August. At first I thought the problem was simply because my computer's IP had changed when I last switched routers, but I fixed the IP, and it still didn't work. That's when I started doing ping tests and discovered the weirdness - that my phone sees and can talk to the router, and vice versa, but not other computers on the LAN.
 
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Thanks so much for responding! :)
You're welcome!

I'm thrilled to find that you're a Linux user. It's all I use...and let's just say I'm known around here for doing a wee teensy-weensy bit of proselytizing about its greatness. :eek: :D :D

Okay, so the addresses you listed for the computers, are they static?

Can you access either computer using a file manager on your phone?

If you don't already have a terminal emulator on your phone, this would be a good time to get one. Two that I use are Terminal Emulator for Android and Termux.

Using a terminal, please post the output of the ping command. (I don't know whether you need help with its syntax. If you do: type 'ping -c4 192.168.1.68' and then 'ping -c4 192.168.1.66' without quotes.) A screenshot after each command would be good. Here are examples of mine:

First, pinging my System76 laptop, whose static address is 192.168.1.123:

Screenshot_20191016-141531.png


and then the nonexistent 192.168.1.120:

Screenshot_20191016-141557.png


Let us see!
 
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Literally, as I was unplugging and reconnecting the router, I was thinking, "Sigh... what a pointless inconvenience. As if THIS is going to fix the problem." ;)

MoodyBlues: It's solved now (dumb quirky router), but I'm nonetheless taking you up on your recommendation and installing a terminal emulator! :) I've been using Linux since 1998, when I built my first computer out of scrap. It's such a great environment for... well, doing things. Anything you think of, rather than just "running programs that other people made". Can't think of a word that fits a certain pattern? Regex grep /usr/share/dict/words! Want to write a bot or to scrape data out of a website? Wget/curl and/or python! Something more complicated? Hey, C++ compilers are stock. It's the operating system equivalent of a well-stocked workshop, at your fingertips. :)

(BTW, I've only interacted briefly on this forum, but thanks for being so nice and helpful! :) )
 
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Oh my freaking god. Now you've made my feel like a complete moron. ;) Here I was trying things like flushing the arp cache and digging through routing tables, and the answer was, "Have you tried turning it off and back on again"?

*facepalm*

Thanks for reminding me to try the obvious first!!! :)
That fixed it? Oh goodness...

I was typing my response when Danny slipped in there. I'm glad it's resolved!

PS We all have those face-palm moments. :D
 
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MoodyBlues: It's solved now (dumb quirky router), but I'm nonetheless taking you up on your recommendation and installing a terminal emulator! :)
Excellent! It'll come in handy many times.
(BTW, I've only interacted briefly on this forum, but thanks for being so nice and helpful! :) )
You're very welcome. I hope you hang around!
 
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