Long running Wired Device losing DHCP, Internet but remains connected to network?

[marsamania]

Hi All,
New member. I found this forum after suffering some strange issues with my new AX88U and hoping someone might have some ideas.

**TLDR** - See my latest reply as most of this seems irrelevant. I thought the issue was related to a TP-LINK device but its all related to devices hard wired to the router that are *Always on*.

I have a AX88U router in my office and I have run a CAT7 cable from my office to my living room where a TP-Link EAP225 AP is cabled in and extends my WiFi network.

What I am seeing is that after a number of hours probably 12+ my TP-Link devices lose internet access and its like the devices are present on the network (can ping them from my pc which is cabled directly into the router) But those devices can't see past the TP-Link.
I had this exact same set up with my old router a Netgear D7800 and never had an issue in all its years of operation.
I Upgraded to the AX88U router due to now having 500mbps and my old router maxed out around 250mbps.

I've done the following troubleshooting:
I unplug the cable from the TP-Link and plug a laptop into the cable.
The laptop is unable to get an IP via DHCP. I can set a static IP and then from my desktop PC I can ping the laptop. But the laptop seemingly has no network access and can't even ping the router.
My TP-Link is set as a static IP that is outside of the DHCP range. In case it matters My IP's are configured as :
Router 192.168.1.254
TP-Link 192.168.1.45
DHCP Range is: 192.168.1.64-253
Rebooting the router does resolve the issue for another 12 hours or so then the problem happens again. It's like the router decides to allow no network to that specific port after a period of time and only a reboot solves it.
I have even unplugged the other end of the network cable and switched my desktop PC to that seemingly "dead port" and my pc cannot see the router once this weird state has started. The router can see a device connected at 1Gbps but seemingly the device cannot see the router until rebooted.

I feel the issue is somehow linked to the TP-Link and Routers interaction. I have noticed the very first time I plugged the TP-Link into the router it did appear as a "connected device" but since it hasn't appeared since and only the devices connected to it appear and they appear as "wired" as thats how the TP-Link AP is connected to the router. It's like after so many hours the router decides to kill all network traffic to the TP-Link on that port and the port isn't usable again until the router is rebooted, but it still shows as connected and any device connected to it (providing they set a static IP) can be seen.

I've also tried putting a 5 port hub between the router and TP-Link and put other devices in the hub too and the same behaviour happens. The port connecting from router to Hub just seemingly dies and all devices plugged into the hub lose network (except to each other which I imagine is the separate hub still routing traffic between them). It seems anything I plug this TP-Link into eventually dies until rebooting the router.

*UPDATE*
I had the issue happen again this afternoon so I did a bit more testing.
For clarity cabling set up is
Router > 5 port Hub > TP-Link
Also in 5 port hub I plugged laptop for debugging.
Laptop couldn't obtain IP via DHCP only static. But once done I could connect to it to share files and it could connect to local network file share. Just seems to be internet access that dies.
I couldn't ping router from Laptop nor could router ping laptop. Even though it lists laptop in list of connected devices and Desktop PC could also ping and connect to laptop (which is cabled directly into router)

Is there any kind of firmware setting that could be causing this? - I was wondering if there was like some weird security feature that sees all these different devices connecting via the 1 port and it triggers some like safety feature on the router to isolate it?

My Firmware version is: 3.0.0.4.384_9559
I know its not the latest, but a reason I brought a custom router was to use my own internal DNS (Raspberry Pi running PI hole for ad blocking) and the latest firmware is bugged for DNS so I downgraded a few versions to see if it resolved my issue above but it hasn't.

Port 4 is currently where I have my wired hub (which has my TP-Link plugged in) plugged into the router and this is in the log.

I'd appreciate any suggestions people might have. Reboot always causes it to be stable again for a while until this unknown scenario happens again.

Apr  3 11:30:45 kernel: eth4 (Ext switch port: 3) (Logical Port: 11) (phyId: b) Link UP at 10 mbps full duplex
Apr  3 11:30:58 kernel: eth4 (Ext switch port: 3) (Logical Port: 11) (phyId: b) Link DOWN.
Apr  3 11:31:01 kernel: eth4 (Ext switch port: 3) (Logical Port: 11) (phyId: b) Link UP at 1000 mbps full duplex
Apr  3 11:31:02 kernel: eth4 (Ext switch port: 3) (Logical Port: 11) (phyId: b) Link DOWN.
Apr  3 11:31:05 kernel: eth4 (Ext switch port: 3) (Logical Port: 11) (phyId: b) Link UP at 1000 mbps full duplex
Apr  3 11:34:45 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) (phyId: 9) Link UP at 1000 mbps full duplex

 

[marsamania]

So i thought this issue was resolved.
Last time I was here I found the fantastic merlin firmware and installed the latest version of that (at the time) and everything has been working fine.
But tonight my issue has appeared again. This time 2 long running wired devices "died" at the same time.

Symptoms are:
Both devices can be pinged by other network devices.
Router is unable to ping them
They are unable to ping router
They are able to ping other devices on the network.

Both are static IP devices, if I switch them to dhcp they cannot get an IP.

Neither can get online Presumably because they *think* they can't see the router.

If I plug another device into the ports they're using, that device has the same issue, different cable makes no difference.
My pc which gets turned off nightly has never suffered this issue.

Any ideas what this might be? Has anyone encountered this with their *always on* hard wired devices?
Wondering if mine is just faulty but its weird as detailed above, they still appear on the network. but DHCP and internet access is gone for them.

 

[venture996]

I would do a clean reinstall of the router, sounds like some memory might be forked. Lots of instructions about how to do this, and then manually apply settings (do not restore from backup)