April 20th, 2012, 09:23 PM #1
- Join Date
- Dec 2008
Problems connecting modem and router
My ISP is AT&T and I have a Westell 6100 modem. I had a DIR-655 router for a number of years but when a nearby thunderstorm occurred almost a week ago, the router evidently was hit by an electrical shock and died on me.
I then went out and bought a Netgear WNDR3800 router. But connecting the new router and the modem has been very difficult. There is an Ethernet light on the modem and an Internet light on the router, and when the WAN port on the router is connected to the Ethernet port on the router, both those lights are supposed to be on. However with the Ethernet cable sent to me by Netgear with the router, as well as other Ethernet cables I already had and have been using for years ( I had two desktops and a network printer connected to my old router ), I have had trouble connecting he router and the modem.
1) The short yellow cable which Netgear sent me to connect between the WNDR3800 router and the DSL modem does NOT work.
2) Another short yellow cable that I had previously used to connect between my old router and the DSL modem does NOT work when used to connect between the WNDR3800 and my modem.
3) A long blue cable that I have previously used to connect between one of my desktops and my older router, when used as a connection between my WNDR3800 router and my modem, does NOT work.
4) A second long blue cable, which I would swear is exactly the same type as the first one, and which I have previously used to connect between my other main desktop and my old router, when used to connect between my WNDR3800 and my modem DOES work. Unfortunately I need this cable to connect my main desktop to the router ( or directly to the modem when I cannot get the router to work ).
So I need to get a reliable cable to connect my router to my modem that works.
Now my problem is:
1) What is going on with these cables ? Amazingly the cable sent to me by Netgear does not work. Anyone have any idea what is going on ?
2) How do I get a short yellow cable that connects between my WNDR3800 and my modem which is guaranteed to work ? I need the only cable which does work to connect between my main desktop computer and the WNDR3800.
I am a computer geek but I admit I am dazed and confused by this cable problem and why just 1 of the 4 Ethernet cables work as a connection between the WNDR3800 and the DSL modem. I am also confused by why the cable sent to me with the WNDR3800 router fails. Is any of this a problem of the DSL modem and a faulty Ethernet connection ? But if I connect a cable from my computer directly to the DSL modem I have no problems so it seems it can hardly be a DSL modem problem.
Most importantly is there any way to troubleshoot this problem, to determine which component, the new router or the modem, has some sort of defective Ethernet connection to it. I just can not believe that the Ethernet cable sent to me by Netgear would be completely defective ( it looks brand new ), as well as all the other Ethernet cables ( but one ) I have and which I used successfully in the past. I feel that something must be wrong on one of these devices and that buying more Ethernet cables is a waste of money.
I would appreciate the advice of anybody who can help me track down this problem.
April 20th, 2012, 11:13 PM #2
If you can get it to work connected direct,from computer to modem, that is you test bed for the cables.
If the cables are OK they all should work in that setup, end of story.
You can ring out the cables with a multimeter, or test light also.
There are only 2 types of ethernet cables.
Cross over, and regular, and cross over cables are becoming increasingly rare, as most devices don't need.
them any more, but most if not all can still use them.
The only time you need them today, is going directly from computer to computer.
You can visually check if any of the cables are cross over.
If the cable is a regular cable, both ends are wired exactly the same.
If it is a crossover 1 end will have 2 pairs reversed.
Describe the ports on you router, and how you are plugging them in.
Normally there is an up link port, and 4 regular ports.
If you have a regular cable, you use the uplink port.
If you have a cross over, you use the regular port, but most, if not all devices nowadays have self negotiating ports, so a crossover cable can also be used, in the uplink port.
The last generation of uplink ports where not self negotiating, but had a manual switch to change the port from a regular to an uplink.
So far it sounds like the router, but until I understand what is going on with the cables, I hold my judgment.
Like most computer hardware, there is no way to test, except by substituting parts.
I have had switches, and 1/2 you router is a switch, that had physically bad ports, that made intermittent connections.
Plane old routers, only have an in port, and and out port, so the 4 regular ports, are the switch side.
The first thing I would do is figure out the cables, because you now it is a problem, and you have to clear that up, before anything else can be trouble shot.Hard Sayin Not Knowin
April 20th, 2012, 11:23 PM #3
Ok, I'm really confused now.
The Westell 6100 modem, is a modem/router, with no switch built in.
Why a second router????? It is possible, but you have to change settings, to use it as a second router.
The only thing I can think of, is your old router had the router portion disabled, and you where using it as a switch.
You would probably use the regular port, not the uplink, but the port would have to be self negotiating, or a crossover cable, would be needed.
I'm trying to remember how to disable routing.
I think you disable DNS.
All you needed is a switch, not a second router.
A least as far as I can see, with the info provided.
Last edited by stroyal; April 20th, 2012 at 11:35 PM.Hard Sayin Not Knowin
April 21st, 2012, 08:37 AM #4
- Join Date
- Dec 2008
But if I use one of those cables to connect my modem to my router, it works whereas the other one does not. Neither the shorter yellow cable whiich was sent with the router to connect it to the modem, nor a previous shorter yellow cable which I had used to connect my old router to the modem, will work in establishing a connection between my new router and the modem.
Clearly to me something is wrong with either my modem or the new router. How can I troubleshoot this problem ? You said:
"You can ring out the cables with a multimeter, or test light also."
I am not hardware technical enough to know what this entails. Can you explain it to me ? Is a multimeter something one buys to test the Ethernet connection on a device, such as my router or modem ? Do I get it at an electronics store ? How does it work ?
The router has 1 Ethernet WAN connection and 4 Ethernet LAN connections. The modem has a single Ethernet connection. The modem may be a router/modem but since it only has a single Ethernet cinnection it can hardly serve as a router. I do have the modem set for Bridge modem when connected to the router.
To connect my router to my modem I connect the WAN port on my router to the Ethernet port on my modem. When this happens a connection is established when the amber Internet light on the router is on and the amber Ethernet light on the modem is on. As explained in my OP, only one of my long blue cables works and neither of the shorter yellow cables work to establish this connection.
Thanks for the explanation about cross over and regular Ethernet cabling. I hardly think Netgear would send the wrong type of yellow cable as part of the new router package. With the other Ethernet cables I have it is impossible for me to tell if it is croosover or regular since they are all closed at the end.
I appreciate your responses and help.
April 21st, 2012, 10:51 AM #5
I've never seen a cat 5 plug you can't see through, they are clear plastic.
Don't focus on my first post, I didn't know you were connecting 2 routers.
You can't have 2 Routers, without changing the settings in the 2nd one.
Routers only have 1 port, as I said, a router with more than 1 regular port is a router/switch
A router can pass out 225 addresses, by that logic, it should have 225 regular ports, not 4.
A multi meter is voltage ohm tester, and if you don't have one, and have no other use for it, don't waste your money.
You can get a cheap test light at any automotive store.
The test will only tell if one of the wires is broken, it won't tell you if it is a cross over cable, without a lot of thinking.
It is much easer to look through the plastic plug with a magnifying glass, and see if it is a crossover.
A cross over or a regular should work on a modern device.
All I can say is your problem is you are improperly, and unnecessarily. connecting 2 routers together.
If you want it to work, disable DNS, in the second router, and plug into port 1, instead of the ethernet port.
You can wait for the real network guys, but this isn't a high end network problem, it is a level I work on all the time.
Finding out what is going on with the cables, should shed more light.
Last edited by stroyal; April 21st, 2012 at 11:14 AM.Hard Sayin Not Knowin
April 21st, 2012, 11:46 AM #6
A cheap place to buy cables, is Home Depot, or Lowes.
They have a pretty complete wired network section.Hard Sayin Not Knowin
April 21st, 2012, 01:33 PM #7
- Join Date
- Dec 2008
You are right, I can see through the plastic of my cables to see the wires. But all the cables are straight through cables and there are no crossovers.
I did find a single short yellow cable which works to connect my WNDR3800 to my modem. Even there it only works when connecting a particular end to my modem and router. If I switch the two ends, there is no connection. Furthermore, even with the connection working, if I disconnect the cable and then reconnect it between the router and modem, the connection no longer works.
All of this leads me to believe, for better or worse, that the new router I bought has a defective Wan connection. I have decided to send it back to New Egg and ask for a replacement. I can not believe that the cable sent to me with the router, and nearly every other Ethernet cable I have, fails to connect the router to the modem and that there is nothing wrong with the router. Of course the modem might be at fault, but since the modem was working fine with my old router before that old router went out on me, I have to assume it is the new router at fault.
Again, thanks for your help and suggestions.
April 21st, 2012, 02:50 PM #8
I did look it up, why do you think, I changed my diagnosis?
Is this it?
Amazon.com: Westell 6100 DSL Router Modem (C90): Computers & Accessories
And from Westell's own sight.
Westell 6100 | Westell 7500
I could be wrong, but I thought all DSL modems, have a router built in.
I have never seen one that doesn't, but I avoid DSL, like the plague.
I've got a network guy on the way, but he is coming from the UK, so he might be a while.
Don't let his name scare you, he's a good guy.
Last edited by stroyal; April 21st, 2012 at 03:07 PM.Hard Sayin Not Knowin
April 21st, 2012, 06:51 PM #9
- Join Date
- Dec 2008
Unless the modem saying it is in Bridge mode is incorrect, I do not think the problem is that I am connecting two routers. I think the problem is simply that the router's WAN port is defective, else any of my Ethernet cables would connect the router and the modem.
I have already contacted New Egg about getting an RMA to send back the router. Hopefully the next WNDR3800 they send me will work properly.
April 21st, 2012, 07:37 PM #10
The westel is a modem only... It probably got fried at the same time yer router did.◄ it is what it is ►
April 21st, 2012, 10:59 PM #11
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- Dec 2008
April 24th, 2012, 01:22 AM #12
Sorry mate... didn't read the entire thread.◄ it is what it is ►
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