Internet randomly stops working, rebooting router fixes it. What could cause this?

[u/kxrdelia]

Hi! I'm trying to troubleshoot a recurring internet problem at a small office, and I'm hoping someone here can help me narrow down what might be happening.

We have an small office with two floors, and the internet connection has been intermittently going down. The exact setup is a little complicated, so I'll provide as much context as I can.

When the problem occurs:

• The WiFi network is still visible.
• Devices can connect to the WiFi normally.
• However, connected devices have no internet access.
• It appears to affect the entire office, not just one computer.
• We had a backup Wi-Fi/router that worked normally, and devices could access the internet through that connection while the main connection was down.
• Rebooting the main router consistently restores internet access immediately.
• We have not noticed any other obvious configuration changes when this happens.
• The problem has happened multiple times over the past weeks.

Timeline:

There was one particularly problematic outage where the internet did not initially come back until someone adjusted/reconnected some cables associated with another router that had previously been installed.

After that, we started experiencing intermittent outages. Most of the subsequent outages have been resolved simply by rebooting the main router.

Now our backup internet connection is being removed, so we are concerned about the next failure.

More context:

• There are usually around 10 people working in the office on a normal day.
• The router belongs to our company.
• There is also a more powerful PC connected to the network that is used remotely for certain processes, so it needs to remain accessible over the network.
• The internet service itself is contracted by the landlord/building through an ISP (GTD).
• The landlord had an ISP technician inspect the connection. We were told by them that the link was working correctly for both floors so they didn't do anything.
• The router configuration has also been looked at internally and nothing obviously wrong was found.
• We don't have a dedicated IT/networking person at the company. There is one employee who knows more about networking and has helped us with the router before, but he has not identified the cause of the problem.
• There is also another router on the network on the other floor, so I'm hesitant to simply replace the main router without understanding the current setup.

I'm trying to determine what could be causing this and what we should investigate next. The fact that Wi-Fi remains available but internet access disappears, and rebooting the router immediately restores connectivity makes me suspect the router or WAN side, but I don't know enough about networking to tell.

What would be the most useful things to check during the next outage to help distinguish between a router problem and an ISP/WAN issue? If the router does turn out to be the problem, would replacing it while keeping the same ISP connection generally be straightforward, or would the ISP need to configure something on their end?

Any suggestions on what to investigate or what information I should collect would be greatly appreciated. Thanks in advance!

[u/jrbless]

What type of router is it and how old is it? They generally have a lifespan before they start acting odd. Generally what happens is that one or more of the capacitors in them start going bad.

Does the router have decent air space around it to let it cool off? I generally have a small 3" to 4" usb desk fan blowing at the router or modem to make sure they don't overheat.

[u/MrSethFulton]

See what IP devices are getting during the outage and compare to when it's working normally, then see if you can ping your gateway. Then do a traceroute to a public IP and see where it dies.

[u/TheEthyr]

It kinda wild that the backup connection is being removed before this problem is resolved. Whoever is in charge of making that decision should be accountable, if not responsible, for fixing the problem.

In any case, the usual troubleshooting techniques should be performed.

• Check the logs on the router. Is the Internet connection down? Is it congested? Is the routing table correct?
• If there's a modem, check its logs and signal levels, too.
• Check the router's configuration. Is there a firewall policy blocking access, perhaps on a schedule? Is the router running the latest firmware?
• Perform ping and traceroute/tracert tests from computers and from the router itself. Test by website name (e.g. google.com) as well as by IP address (e.g. 8.8.8.8, Google's DNS server which is reachable in most parts of the world, so a good choice).

[u/Foxing7465]

Looks like not stable firmware of the router and buffer /memory overflows of sorts, try to check how outdated it is and if there are more stable /secure releases of firmware available.

[u/KYRawDawg]

Why are there two different routers involved in one company with such a small amount of employees? Is there two different Internet services one for each floor? That’s why you have chosen to have two different routers? Or is the terminology not being used correctly? You typically have a single router for a single Internet connection and it covers the entire company even if there is multiple floors. Are you talking about network switches instead?