Bizarre networking issue


I’ve been dealing with this bizarre networking issue for years now. It’s impossible to google. On the left is my wifi router. On the right is my local Comcast gateway. Pings are randomly dropping. Internet service is disrupted, as you would expect. Router says it’s disconnected from the internet.

Here’s the weird part. Connections that are established keep working. Zoom calls keep working. WoW keeps working. Discord voice keeps working. NEW connections will fail – probably due to DNS. But some existing connections will also fail. Web pages become intermittent. I was just in a Slack conversation with someone when the problem started and my Slack was disconnected.

Rebooting the router OR the modem will fix it. I believe it will also fix itself after an unknown number of minutes / hours. It happens 1-3 times per week, so it’s pretty fucking annoying.

I asked my network guy at work about it and I don’t think he understood me. He mumbled something about IPsec confusing the Comcast modems. We rarely have VPNs running in my house. I cheat and do my work through Chrome Remote Desktop. One time, however, when the problem was occurring my wife was on a Zoom meeting and the second she got off the problem ceased. This was a one-time thing, however. She was on Zoom when this event began and it didn’t go away when she ended it.

The router is fully up to date.

Any ideas?

Here it is after I rebooted the router -


E - I have my router set to reboot every day at 4:02am. Not that it helps.

Nothing to do with DNS, you have pings timing out too. Only thing I can think of is P2P like bittorrent exhausting your router with the number of connections it makes, or possibly the router overheating.

Anyway, I would suggest getting comcast to put your modem in bridge mode and see if that helps. If not, time to buy a new router.

My router’s on that list! It’s an Asus RT-AC88U. 😢

If it’s up to date, my guess would be the modem is your problem then. Give bridge mode a shot and if not have Comcast replace it.

Asus stuff goes bad so much more than people realize. That’s why I stopped using them (personal experience).

Yep, I’ve had absolutely garbage experiences with everything I’ve had from Asus.

My Asus routers have been improved immeasurably by my installing custom firmware on them. I’m using FreshTomato on both my Netgear R7000 and ASUS RT-something-something.

I have come to the conclusion that all consumer routers are consumable items. They are not designed to last. They sell into a very competitive space, have aggressive pricing, designs that are more athestic than functional - all of which adds up to cost cutting in componentry and poor heat management, which conspires to kill them in a couple of years. The best run I have had in recent years is with a Nighthawk R7000 with Tomato, but wifi is disabled on it in favour of Ubiquiti AP’s, which helps minimise additional heat.

Agreed. I went through three of them before I decided it would be better to just buy a cheap blade off ebay and install pfsense on it. Probably not even close to as energy efficient but it’s absolutely stable combined with Ubiquiti APs.

I never had trouble throughout years running DD-WRT and Asus Merlin routers. The trick may indeed have been that custom firmware.

Now I’m running a UDM Pro and it’s also quite stable, although it has its own little quirks.

Yah, ASUS makes great hardware, but their drivers are crap in a LOT of instances. They just aren’t a software dev company.

It was the router, an Asus RT-AC88U. I replaced it with a TP-Link AX5400. Coverage is better and ping jitter is also better. The web control panel is lackluster, but it’s sufficient.


Shame, that was a really high-end router.

I’ll piggy back on this thread since I can’t figure out this problem.

I would appreciate any ideas.

ASUS router died. Replaced it with the a new NetGear router. Used the same SSID and network password so I didn’t have to do anything to any of the devices.

Everything is connected to the network fine, my problem is things keep dropping off the network. They still have WiFi, they just stop talking to other devices. I have Mac’s sharing a drive for instance, and it will just disappear and come back hours or days later, and then disappear again.

I used default settings, and can’t see anything that looks abnormal, but I don’t know how to troubleshoot this. Could reusing the SSID cause problems? Any ideas?

It should not. That’s what I did when I replaced my router, and I’m pretty sure that’s what everyone else does these days too. There are far too many connected devices now to reconfigure them all. (Some of them were even vendor installed and I couldn’t reconfig them if I wanted to.)

I don’t have anything else to offer for your problem, though. :(

So when the devices lose the connection, they can each still get to the internet, but lose contact to other devices on the LAN? Can they still ping each other?

Most home routers have various intrusion and DDoS protections enabled by default, and they usually suck. Could be the router thinks something is suspicious about your traffic and is trying to isolate some of the devices. Does it keep an event log?

Reusing the same SSID shouldn’t be a problem, but changing it and setting up the WiFi from scratch can be a good way to refresh everything. If you too have a huge number of devices and changing them all is a pain, some routers can use multiple SSID or wireless networks.

Yep, that is exactly what is happening, Internet is fine, speed tests are good but they cannot talk to other devices on the network. No they cannot ping each other. I get timeout or a “host is down” message.

I will check to see if I can find a log, thanks for the idea.

I might just start from scratch and see if that helps.

I have a few of these in the log from an hour ago:
DoS attack: Fraggle Attack] from source,port 67 Wednesday, Jun 16,2021 13:08:03

Edit: Found a thread on Netgear’s form that there is a problem with false positives, and this might be nothing.

But then most of the log is just this, repeated over and over:
Wednesday, Dec 31,1969 16:00:00

Australian Bryan Adams fan?

There’s certainly a device isolation switch on current routers that you can throw, so that each device is on its own island. Usually the guest network gets that setting by default. Do you have a guest network set up and did you configure it so that some devices might join that instead sometimes?

Otherwise, yeah, I’d turn off all the random protections they offer for a day and see if that fixes anything.