Cannot ping device in same network, but can ping it from different network

Network topology:

I can ping the wifi device from the server, but not from my desktop or laptop computer. I have no clue how this is possible, it has been messing with my brain for the last couple of weeks and I just can’t figure it out. Hopefully one of you has an idea.

Are you using DHCP to configure the desktop & laptop? If so, what gateway and subnet are you serving to clients?

Post your routing table for the desktop, laptop, and server. (netstat -rn on Windows and ip r on Linux).

Well, since it seems your Server is on a different network, you’ll need to allow ICMP in both directions (DZM<->LAN) respectively. this needs to be done on your pfsense box.

Reread the post. Ping across subnets is working. Ping within is not. Pfsense should not be in play at all.

@Derkades can laptop and desktop ping each other?


It still could if ICMP isn’t allowed from LAN <-> LAN.

If intra-subnet traffic is touching the router, something is wrong.


How “dump” is that switch?

It’s a netgear prosafe gs108 (non plus) switch that has no IP address, layer 2 only

Yes, that works.

I should add, it’s not just ICMP. The wifi device runs a webserver that I cannot access from the laptop or desktop, but when I use sshuttle to connect through the server it works fine.

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Did you check the arp table from all devices ?

On the desktop

Address                  HWtype  HWaddress           Flags Mask            Iface               ether   02:42:ac:11:00:03   C                     docker0               ether   02:42:ac:11:00:02   C                     docker0
pfsense.slot             ether   d8:d3:85:f6:9a:2c   C                     enp34s0                       (incomplete)                              enp34s0                       (incomplete)                              enp34s0               ether   98:3b:8f:bf:62:ba   C                     enp34s0

pfsense.slot is the router (obviously) and is the device I can’t connect to. I’m not sure what it means that the arp table shows (incomplete). It does show a mac address in the router for, 98:f4:ab:f2:8d:80

Yes, subnet default gateway DHCP range

default via dev enp34s0 proto dhcp metric 100 dev enp34s0 proto kernel scope link src metric 100 dev virbr0 scope link metric 1000 linkdown dev docker0 proto kernel scope link src dev br-2513d450bcb9 proto kernel scope link src linkdown dev br-8c27b5d04956 proto kernel scope link src dev br-9efa184c5987 proto kernel scope link src linkdown dev virbr0 proto kernel scope link src linkdown 

Not much out of the ordinary I don’t think, one primary intel NIC and a couple of interfaces for docker and qemu.

Well that makes sense why it can’t connect to it if it doesn’t understand the mac address. Not sure why that would happen though. Do you have another switch you can test?

Since the server connects through the same switch, I’ll try swapping ports for the server and computer.

EDIT: Still same result. I’ll swap the switch with a (managed) switch I have laying around.

EDIT 2: No luck :frowning:

How’s configured? e.g. what kind of device is it, what’s it running?

Make sure that they ALL belong to the same subnet mask, ie /24.

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Likely an IP subnet (typo?) issue on the WiFi device. Of course it could be a bug in the IP stack or some security setting.

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It’s an ESP8266 microcontroller (inside a Shelly switch)

I think your default gateway should be the IP address of the router (aka pfsense virtual machine) and not the hypervisor host which it runs on (in your diagram the machine called “server”).

What’s the IP Address of the PFSense VM?

Side note - Are you running PFSense as a container?

The network stack inside esp8266 can be weird in my opinion.

You could perhaps ssh into the wifi router and run tcpdump -nv icmp and host

And see if the reply is happening but is somehow wrong, or not happening at all.

It is this way.

  • Virtual network VM host has IP address, pfSense has IP address
  • Network pfSense has IP address, desktop, laptop and esp8266 are on this network.

Server network
Guest network
IOT network (not in use currently)
Other network

Not sure that’s even possible? I use QEMU/KVM on Ubuntu