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Scenario (based on real events)

a small business has a "BigCorp" Internet service. One day the Internet goes down after a power outage, and they call BigCorp for help. BigCorp support over the phone checks and verifies connection and it seems to be working on "their end" (whatever that means) but the business still cannot connect to the Internet via end-point computers that are connected directly via Ethernet cables to the router.

So BigCorp rep on the phone asks to disconnect and replug various devices, and even do a "hard reset" on some of them. The Internet still doesn't work and so they claim that the issue is on the "business end" since to them, BigCorp end seems fine.

I was called in to try to troubleshoot before calling BigCorp again for a tech. I am not a network guy but a computer-literate person. Looking at end-point computers, Windows 7's Diagnostic tool said you can't connect to the internet and offered to troubleshoot. It suggested DNS server is unreachable. So I got public IP addresses of several known sites via my phone (i.e. workplace, cnn, my own site), and tried to ping them via CMD. Each came back as "Destination Unreachable". I rebooted computers, did ipconfig/renew, didn't help.

I went to BigCorp cable modem boxes, and there were 5 various devices, which looked like a switch, a router, a cable box, a phone box possibly, and something else. All interconnected in ever-which way and in complexity looking like it was for a business with 100 employees rather than just 6. There were literally over 30 Ethernet cables going from one box to another. All boxes were ON with either steady (or rarely-blinking) lights marked with various labels such as "On", "Link", "Internet". All looked like they were working and connected. But, there was still no Internet. I could only ping 192.168.1.1.

My next step would be to call BigCorp and have the tech come out, because I don't see what else I could do to troubleshoot before calling them. Possibly some BigCorp config unknown to me that got corrupted? BigCorp insisted the issue is on "my end", but my I have no clue what it could be.

Question

Aside from calling BigCorp tech to come out, are there any other specific steps I could do, aside from ones already tried?

To recap, things already tried:

  • powering all boxes on & off
  • doing hard reset per BigCorp direction
  • observing "On", "Internet", "Link" buttons to be in their on state
  • pinging public-facing IP addresses and seeing Destination Unreachable
  • running Windows 7 diagnostic tool,
  • doing ipconfig/renew
  • rebooting computers
  • pinging 192.168.1.1 OK but not any public-facing WWW IP address to bypass DNS

closed as off-topic by Ron Trunk, Ron Maupin Jan 31 '18 at 16:00

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "NE is a site for to ask and provide answers about professionally managed networks in a business environment. Your question falls outside the areas our community decided are on topic. Please visit the help center for more details. If you disagree with this closure, please ask on Network Engineering Meta." – Ron Trunk, Ron Maupin
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  • 3
    Sounds like you did what you could. My guess is the router lost its configuration when the power went out. But you will need to call them. And since questions about networks you don't control are off-topic here. I'm afraid I have to vote to close. – Ron Trunk Jan 31 '18 at 15:38
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    I am not a network guy Step 1: bring in a network guy You need someone who can understand all the boxes and wires. Someone who knows the lingo. – Ricky Beam Jan 31 '18 at 20:58
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There were literally over 30 Ethernet cables going from one box to another.

I wonder if one of the "boxes" you saw was not actually a peice of active network equipment at all but instead was a patch panel for the outlets around the office. That would explain the large number of cables.

So BigCorp rep on the phone asks to disconnect and replug various devices, and even do a "hard reset" on some of them

EEK

If by "hard reset" they mean reset to factory settings that could easilly have made the situation much worse.

are there any other specific steps I could do, aside from ones already tried?

Traceroute can often be quite informative. If this is a "broadband" connection then very likely any public IPs you see in your traceroute mean the packet reached the ISPs network and was dropped inside it somewhere.

You really need to understand what all the boxes do, how they are interconnected and which ones are under administrative control of the client vs administrative control of the ISP and if at all possible get admin access to them without doing a factory reset.

The trouble is right now you don't know if you are dealing with a simple home/SMB router on it's default configuration with a dumb switch to add extra ports and a patch panel to connect the network equipment to the rest of the office or whether you are dealing with a more complex network set-up. Assuming the former when the latter is the actual case could easilly result in either you or a bigcorp tech doing more harm than good.

Trying to connect a computer directly to the cable modem may be worth trying. However some cable accounts may be MAC address locked, so you may need to clone the MAC address of the router for this to work.

My next step would be to call BigCorp and have the tech come out

While this is probablly nessacery I would be wary. They will probablly get you a machine connected to the Internet somehow but they may horriblly break your client's network in the process. If/when you do call them out be careful what you let them touch.

  • Thanks. There was a happy ending to this, the BigCorp came out and "did something" to restore Internet access. Since I left the office, I don't know what they did or how, and neither did the receptionist there, but they are back online. – Dennis Jan 31 '18 at 16:05
  • Also my guess was that hard reset was either a signal they've sent over the wire (?) or maybe they indeed had requested them to press the reset button, which indeed likely wiped out any custom configuration – Dennis Jan 31 '18 at 16:11

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