Modem LAN light not ON while connected to Router

[jsuarez388]

Hi,

I had a ADSL 2 modem plugged to a D-Link router. Worked just fine for a couple of years. One day it just stopped recognizing the modem, but still emitting a wireless signal that I could see on my devices, just no internet connection.

Tried a wired connection and internet was just fine, I reset the router and modem but the problem persisted. Finally switched to a Linksys E800 router. Worked just fine for a couple of weeks, one day the same thing happened, Wireless signal is emitted, there's internet, but LAN light on modem is OFF as well as Internet light on Router is off.

What could be going wrong here? I plugged in another TP-LINK Archer C5 router to the modem and everything is working just fine.

 

[kanewolf]

It is one of three things. Bad cable, autonegotiation of link speed, bad port on the modem. Swapping in a brand new commercial cat5e cable is the easiest thing. After that you would have to check if the port speed of the router can be set in firmware. Third thing would require a new modem.

 

[jsuarez388]

It is one of three things. Bad cable, autonegotiation of link speed, bad port on the modem. Swapping in a brand new commercial cat5e cable is the easiest thing. After that you would have to check if the port speed of the router can be set in firmware. Third thing would require a new modem.

Thank you for your response.

I forgot to mention that I tested this with 4 different cables most of them brand new, and all came to same result. Internet from LAN port of Modem to Router ONLY works on TP-LINK Archer C5.

I don't know what autonegotiation is.

I don't think the port on the modem is bad since I get internet on the TP-Link router and also wired directly to computer.

If the port speed can be set on the router configuration, what should I aim for?

Is it possible that the modem is damaging the Ethernet port on the routers? Seems odd that the same problem happened on two different routers. I still have to test these routers on another modem and see if I get internet from the modem to the router

 

[kanewolf]

Autonegotiation is the two devices on either end of an ethernet cord trying to figure out what speed to transmit. You will need to figure out what speed the modem can transmit. It will either be 100 or 1000. You would then set the WAN port speed in the router to that speed.

 

[jsuarez388]

Autonegotiation is the two devices on either end of an ethernet cord trying to figure out what speed to transmit. You will need to figure out what speed the modem can transmit. It will either be 100 or 1000. You would then set the WAN port speed in the router to that speed.

Thanks for the clarification. But, if this Modem was already working just fine with either of these two routers, is it possible that because of autonegotiation the ethernet port on the routers stopped working?

How can I figure out what speed is the port in the Modem to select the same speed on the routers?

 

[kanewolf]

Autonegotiation is the two devices on either end of an ethernet cord trying to figure out what speed to transmit. You will need to figure out what speed the modem can transmit. It will either be 100 or 1000. You would then set the WAN port speed in the router to that speed.

Thanks for the clarification. But, if this Modem was already working just fine with either of these two routers, is it possible that because of autonegotiation the ethernet port on the routers stopped working?

How can I figure out what speed is the port in the Modem to select the same speed on the routers?

You will need to find a spec sheet for the modem.