Issues with tcp request dropping devices off the network?

General
1

Okay, so here's a strange one that I'm just hoping someone can shed some light on.

I have a house alarm with an IP module. This module connects to my network via a Cat5 cable, and allows me to open up a TCP connection to listen for changes in status (i.e. motion triggered, alarm armed etc.)

It has been working brilliantly for months, and I have a node-red flow with a tcp-request node that opens the connection, and has the return set to "never - keep connection open".

However, over the last few weeks/months, every few days the module just drops off the network. I can still see blinking lights on my switch, and on the module itself indicating a connection, but the TCP connection is lost and I can't ping the module.

I've been using Wireshark to sniff the packets, and all it shows is a bunch of successful TCP connections, and then the module sending out ARP requests to find the address of the gateway, and getting a response. But then, out of nowhere, I see some TCP retransmission issues - and then, it's gone. All that follows is the endless list of my Raspberry Pi (running node-red) ARP requesting "Who has 192.x.x.x?" and getting no response from the module.

I then have to factory reset the module, set it up again, and then it works for a week or so and then repeats.

The alarm company swears they've had no issues with the firmware I'm using, and they're claiming it is a network problem. But nothing in my network has changed.

So I'm just wondering if there is something I'm doing wrong with the TCP request node and/or if there is a better way to do what I'm doing that won't cause this error.

Any help would be greatly appreciated!

2

Welcome to the forum @thecrane

If you can normally ping it but can't ping it any more then it isn't a node-red issue. Can you ping it from another device on the network? That would rule out the device running node-red. Have you tried resetting the router?

Edit: Also you say you have to do a factory reset, does that mean a power cycle does not work? If you have to do a factory reset I can't see how it can be anything other than the device.

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I would strongly suggest this module is at fault. Even if node-red or your flow is "upsetting" it (with ill timed commands etc) it still shouldnt fall over. And to add a further nail, the fact restarting this module restores connectivity implicates it further.

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Great - thanks everyone. I figured it must be the hardware. I'll try and get a new module to test.

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