Troubleshooting Ethernet issues

[IAmAndre]

Hi,

 

I have two TP-Link routers after I upgraded my old one, however none of them has a working Ethernet connection and I need help troubleshooting this issue. I've tried several 3 cables so I don't think it's a cable issue. I only have a desktop, which is another room (I have a 30m cable) and a laptop with no Ethernet port (I have a cheap USB C dock).

 

So what happens on the new router is that although it has multiple Ethernet ports (picture attached) only one of them (port 2) shows signs of activity through the lights in front when I plug it, and that's only 50% of the time. So when it does get connected, it's recognized on the computer but I have no internet access and I can't even access the router's admin panel.

 

On the old router, plugging the cable in any port makes the relevant light on the front turn on but then there is no activity on the computer.

 

Everything was working automatically on my very first router, which is dead so I'm not sure if I'm missing something, and more importantly, I don't know how to troubleshoot the issue.

 

Any help?

[RageTester]

30 meters is a lot of cable that can do wrong...also maybe it somehow only works in one direction...

I assume at least wifi works. If you can't get into admin panel via cable, there must be a password on the router itself... Reset the router, check if there are any settings that can enable/disable LAN ethernet ports?

 

I don't see the attached picture... you mean links to the shop?

I have my own problems with new routers... somehow old ones seem to be more reliable... Can you return the new router to be replaced?

 

 

 

[Windows7ge]

With these consumer units there's not a whole lot to do check:

Internet -> Modem -> Router -> Switch -> Your devices

Frequently ISPs provide a Modem/Router combo and often a 4 port switch is collapsed in the router.

 

I've seen cases where the router doesn't have DHCP enabled by default for whatever reason. If you can find what network the router is suppose to broadcast you can give yourself a static IP and see if if you can login to the WebUI.

 

Outside of that you can try resetting the router. Try a different router. You've eliminated cables already.

 

Did you try a different computer? Does wireless work? Can you access the WebUI from there?

[IAmAndre]

2 hours ago, Windows7ge said:

With these consumer units there's not a whole lot to do check:

Internet -> Modem -> Router -> Switch -> Your devices

Frequently ISPs provide a Modem/Router combo and often a 4 port switch is collapsed in the router.

 

I've seen cases where the router doesn't have DHCP enabled by default for whatever reason. If you can find what network the router is suppose to broadcast you can give yourself a static IP and see if if you can login to the WebUI.

 

Outside of that you can try resetting the router. Try a different router. You've eliminated cables already.

 

Did you try a different computer? Does wireless work? Can you access the WebUI from there?

Wireless works. I tried on my laptop too as I mentioned.

[Windows7ge]

1 minute ago, IAmAndre said:

Wireless works. I tried on my laptop too as I mentioned.

I expect the WebUI should have a section that shows you what ports are active/have a connection. What does the WebUI report in there when a device is connected to a port?

[trufret]

Sounds like the switch ports on the new one are dead but there is some checking you can do.

 

You've said you tried connecting it with multiple cables so likely the cables aren't the problem but just to make sure, are they all purchased cables (ends not crimped on by you) and undamaged?

 

You mentioned your laptop has a USB C dock, does that dock have an Ethernet port on it?

If so, does connecting that to the router produce the same results as the desktop?

 

If you want to make sure the cables are good you could directly connect the desktop to the laptop dock and manually assign IPs to both Ethernet interfaces. if you can ping pack and forth then the cables should be fine.  All NICs in the past decade plus should be auto sensing so you shouldn't need a specific crossover cable to do this anymore.

 

When you plug in the desktop to the router and it does recognize the cable (assuming your not manually setting an IP), does it get an IP address that starts with 192 or 169?  If it's 169 then you are not getting a valid IP from DHCP on the router.  The fact that it works on wireless suggests the DHCP server is working on the router but not through the switch ports.

 

If everything else is working but the router switch ports I'd suggest returning the router for a new one as it's likely had some internal failure of the switch ports. I've certainly seen that often enough with home equipment.

[IAmAndre]

55 minutes ago, trufret said:

You've said you tried connecting it with multiple cables so likely the cables aren't the problem but just to make sure, are they all purchased cables (ends not crimped on by you) and undamaged?

Yes, I used the cable that came with the router and another one that I bought yesterday.

 

56 minutes ago, trufret said:

You mentioned your laptop has a USB C dock, does that dock have an Ethernet port on it?

If so, does connecting that to the router produce the same results as the desktop?

Yes, that's what I used to connect the router to the laptop and it's not recognized at all on both routers. However I mentioned that I'm using a dock because the dock could be faulty as well so that's an extra factor.

 

59 minutes ago, trufret said:

If you want to make sure the cables are good you could directly connect the desktop to the laptop dock and manually assign IPs to both Ethernet interfaces

That's very interesting. I'll try it tonight and see how it goes. I also just realized that I don't need an internet connection for my tests so I'll just unplug the routers from the RJ11 cable and bring them all to my office and run some more tests. I'll publish the results tonight or tomorrow.

 

Thank you for the detailed reply!

[Slayerking92]

18 minutes ago, IAmAndre said:

Yes, I used the cable that came with the router and another one that I bought yesterday.

 

Yes, that's what I used to connect the router to the laptop and it's not recognized at all on both routers. However I mentioned that I'm using a dock because the dock could be faulty as well so that's an extra factor.

 

That's very interesting. I'll try it tonight and see how it goes. I also just realized that I don't need an internet connection for my tests so I'll just unplug the routers from the RJ11 cable and bring them all to my office and run some more tests. I'll publish the results tonight or tomorrow.

 

Thank you for the detailed reply!

If you are using RJ11 cables, that would be the problem.

 

[trufret]

2 minutes ago, Slayerking92 said:

If you are using RJ11 cables, that would be the problem.

 

Haha yeah, I'm assuming he meant RJ45

RJ11 is usually for telephones and is 2 pairs

RJ45 for networking and is 4 pairs

[IAmAndre]

7 minutes ago, Slayerking92 said:

If you are using RJ11 cables, that would be the problem.

 

 

2 minutes ago, trufret said:

Haha yeah, I'm assuming he meant RJ45

RJ11 is usually for telephones and is 2 pairs

RJ45 for networking and is 4 pairs

RJ11 cables are used for ADSL-like connections so the router is connected to an RJ11 câble ans thé internal routing is done with RJ46 cables.

[IAmAndre]

3 hours ago, trufret said:

Sounds like the switch ports on the new one are dead but there is some checking you can do.

 

You've said you tried connecting it with multiple cables so likely the cables aren't the problem but just to make sure, are they all purchased cables (ends not crimped on by you) and undamaged?

 

You mentioned your laptop has a USB C dock, does that dock have an Ethernet port on it?

If so, does connecting that to the router produce the same results as the desktop?

 

If you want to make sure the cables are good you could directly connect the desktop to the laptop dock and manually assign IPs to both Ethernet interfaces. if you can ping pack and forth then the cables should be fine.  All NICs in the past decade plus should be auto sensing so you shouldn't need a specific crossover cable to do this anymore.

 

When you plug in the desktop to the router and it does recognize the cable (assuming your not manually setting an IP), does it get an IP address that starts with 192 or 169?  If it's 169 then you are not getting a valid IP from DHCP on the router.  The fact that it works on wireless suggests the DHCP server is working on the router but not through the switch ports.

 

If everything else is working but the router switch ports I'd suggest returning the router for a new one as it's likely had some internal failure of the switch ports. I've certainly seen that often enough with home equipment.

OK so I just unplugged everything, brought all the routers in my office, did some testing and didn't encounter any issue whatsoever. Everything was recognized. Brought the router back to the living room, plugged it again, and boom everything works fine. I'm not sure what happened. Maybe starting the router with no RJ11 connected kind of reset something but as of now everything is working fine and my ping even improved my 2-3 ms. If it ain't broke...