D6200 stops routing

[Jimchjones]

Had this router for a few years now, but the last few weeks have been running into a weird problem. It apparently stops routing. The link is still up, and packet counts are increasing, but a client device can't access anything on the wider net, not even ping. Disconnecting and reconnecting the Internet port usually resolves it, and a power cycle always has. Sometimes the failure to route is only devices on the wireless LAN and the devices on the ethernet port continue to be fine. Diagnostics on the router, pinging from the router to the net for instance still pass. Nothing in the router logs, although I've disabled logging of "known DOS attacks and port scans" because port scans are continual, so even if something of interest was in there I'd struggle to find it. It happens I suppose a couple of times a day, but extremely varriable. No pattern I've seen. I've reloaded the router firmware without it making any difference. I'm at a loss of how to progress. It seems as if the problem should be with the router, but I have a reluctance to replace something that appears to be working 99% of the time unless I have better evidence that its faulty or very desperate.

Any ideas? I like to think myself not totally ignorant in infrastructure matters, but am currently out of ideas of how to progress it.

[michaelkenward]

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@Jimchjones wrote:

Had this router for a few years now

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I get a bit worried when people describe the D6200 as a router. It raises a few questions.

This is a DSL modem router. Is that how you are using it? Or is it simply a router? (Or even modem only?)

You said:

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a client device can't access anything on the wider net, not even ping.

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What client is this? How is it connected to the Internet? WiFi? Wired?

What errors do you see?

Do the LEDs give any clues?

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....I have a reluctance to replace something that appears to be working 99% of the time unless I have better evidence that its faulty or very desperate.

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You are talking about a device that Netgear launched nearly a decade ago (2014). It is several generations of WiFi behind the curve. Then again, if you are using it as a DSL modem you won't have the fastest Internet on the planet.

But if you are using it in router only mode, it may be time to send it to recycle heaven.

[Jimchjones]

OK thanks it certainly seems to be routing that's the problem, since local client to router ping (and all else) seems to work fine, and ping etc from router to random Internet hosts is also OK, but ping From Client To internet Hosts fails. Windows And android clients. 

[michaelkenward]

Sorry, but none of that makes much sense to me.

I still have no idea what you are doing and where it goes wrong.

[Jimchjones]

You must excuse me, I've spent a lot more time with Cisco routers and leased lines than I have had anything to do with ADSL so I'm probably not using conventional phrasing..

So the D6200 is plumbed into the local copper for an ADSL connection to the net, and we have a mix of wired and wireless devices using it to connect to the net. What happens is that sometimes just wireless and sometimes all devices lose connection to the net. The 6200 home page is still accessible on the local 192.168 address though, so the devices are communicating with the 6200 just fine. I can (of course) ping the local interface and so on. If I then get onto the router management page and look at stats and diagnostics then the internet link is reported as being up and I see packet counts increasing on the internet link, and using the diagnostic utility I can ping hosts on the net from the router. However I can't ping or otherwise connect to the same net hosts from my devices. If I disconnect and reconnect the ADSL link in software on the 6200 then connectivity will come back, as it will if I power cycle the 6200. I don't see any entries in the router log to give any clues: it doesn't report the link dropping or an attempt to reauthenticate. I've reloaded the firmware, but I haven't tried returning the 6200 to factory defaults.
So my presumption is there is a routing failure of some kind. Could be NAT or any number of other things I suppose.  I could just go and buy another router I suppose, but I have a rooted objection (sorry) to buying kit at random in the hopes it will fix something: I'd much rather diagnose the problem properly first. I suppose I may as well raise a call with my ISP to see if there's anything visible at their end, but it feels like a local problem to me. 

[michaelkenward]

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@Jimchjones wrote:

What happens is that sometimes just wireless and sometimes all devices lose connection to the net. The 6200 home page is still accessible on the local 192.168 address though, so the devices are communicating with the 6200 just fine.

Are these just WiFi connections that stop are does the wired network die?

Is the SSID still visible?

What do the LEDs on the D6200 show?

Is the DSL link still live?

I always refer people to the manual and the bit Troubleshoot with the LEDs

I am more familiar with VDSL and a standalone modem. It gives me the chance to use a router that wipes the floor with anything you find in a modem/router, especially something as ancient as the D6200 from a decade ago. This means that I can see what the modem is up to. Sadly, DSL has a habit of going AWOL. This naturally kills the Internet connection. I then run through a diagnostic sequence to try to bring the DSL back to life.

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I'd much rather diagnose the problem properly first. I suppose I may as well raise a call with my ISP to see if there's anything visible at their end, but it feels like a local problem to me. 

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Agreed. That's why I asked my questions. Personally, I find talk of "pinging" to be pointless. All it show is that I know some fancy techy stuff without actually telling me anything useful about the state of the network.

[Jimchjones]

OK, well thank you for your thoughts and contribution
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I'm afraid ping tests etc are how I was trained to diagnose networking issues.