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

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?

 

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.

 

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!!!

 

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! )