Network issue

After a switch I have 2 internet jacks, lets say A and B. Both currently have a single computer plugged in and they get internet and can network with each other.

I have another switch because I want to hook up multiple machines at one location. At location A I plug the switch in, then plug computer A into switch. Everything works fine. When I do the same thing at location B I have no internet access.

How does that make any sense? I know every single piece of hardware and wire i'm using works because it works set up at location A. I can't figure out what's wrong. I can't buy another switch because I know this one works correctly.

I'm not sure if it makes any sense, but I switched the short cables from the first switch between A and B and it works the opposite now. So that short cable going from switch 1 to the B location will allow a single computer to access, but not a switch. Hmm.

But since I only need the switch at location B and now that works I guess problem solved. Though i'm still curious as to whats going on.

what do you mean by "switch"? a splitter? is there just an input and output and you just switched them?

if you mean 2 different locations as in 2 different rooms, then it's probably a signal issue. where it splits in the basement perhaps the "weaker" port is going to the location where the internet won't work.

also there's only so many times you can "split" a signal before things like internet and digi cable won't work. you could run 14 analog tvs with the same signal that would only power 1 internet connection.

i'm still not sure if i'm understanding the issue correctly, though.

A switch is basically a router, but no wireless signal. It allows you to create multiple ethernet jacks from 1. Like this thing:



You run an ethernet cable to it from your modem or router and plug it into one of the jacks, then all the other jacks can be used.

are you running this switch off a modem or a router? is it the same in both locations? by locations do you mean separate rooms or separate physical locations in the same room but with a different coaxial outlet?
are there 2 modems, 2 routers..? or just one modem/router which is hardwired to each of these locations?

i still don't quite understand but i'm getting there and now i want it figured out.

This is how it is set up.



And this is essentially what I was talking about. There are actually 28 different green wires going to various locations all over the office, and about 15 of them are plugged into the first switch, but I only drew the 2 I am talking about for simplicity. A and B are in different offices. There is only one plug at location B, and I needed to hook up a computer and a printer to the network. The switch is essentially just a splitter. It is externally powered and there is no "signal" to lose, it just links between the two devices plugged in.

assuming you used the same jack on the switch at location A (ruling out a possiblity of a faulty jack on the switch itself) i would look to one of the ethernet cables as a culprit. if you switched the cables and it worked for a computer but not the switch it really could just be a screwy jack on the switch that has a loose grip, in which case you could use a different jack.

if it's definately the same jack on the switch but only works at a certain location then i'm stumped.

in the above diagram, at location b, can the printer access the network through the switch, or does nothing work through that switch?

I used the same jacks on the 2nd switch, so it's not the switch or any of the cables connected to that switch.

I swapped the 2 cables between the first switch and the wall/green lines. One of those cables will only work when connected to a computer and NOT the switch. I only need a second switch at a single location though, so i'm using the cable that is letting me.

You use DSL?
Is that the one where if you're on the internet and you answer the phone, the internet won't work?


Wouldn't that same rule apply to using two computers? I use cable though so I could be way off.

Replace the second switch with a router.

edit didn't see the thing about it splitting to 28 different computers. My thought would be that the computers behind the second switch aren't being assigned an IP and they're essentially trying to share the same IP which is why it isn't working.

Fungus Gnat said:

Replace the second switch with a router.

edit didn't see the thing about it splitting to 28 different computers. My thought would be that the computers behind the second switch aren't being assigned an IP and they're essentially trying to share the same IP which is why it isn't working.

Click to expand...

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I think he got it.

Or hang a HUB off it, depending on your router, there may only be 1 port which allows you to do DHCP. I know the Linksys and D-Link require the specific port.

Good Luck

ganjames said:

You use DSL?
Is that the one where if you're on the internet and you answer the phone, the internet won't work?


Wouldn't that same rule apply to using two computers? I use cable though so I could be way off.

Click to expand...

No, you are thinking dial up which dials to an isp phone number over the phone line. DSL is high speed internet transmitted over the phone line, but it uses a different frequency than the audio for a phone, so the two can be used simultaneously without interference. It is just as fast as cable, but it is a dedicated line unlike cable which is shared. By shared I mean the cable company connects a super fast connection to the internet, then connects many different subscribers to the same connection, so you are sharing your physical connection to the internet with all the cable internet users in your proximity. We have an allotted amount of bandwidth over dsl that is dedicated, it doesn't slow down when other people access the internet. Cable is shared in blocks, and if other people sharing your block hog bandwidth it slows your connection down.

Fungus Gnat said:

Replace the second switch with a router.

edit didn't see the thing about it splitting to 28 different computers. My thought would be that the computers behind the second switch aren't being assigned an IP and they're essentially trying to share the same IP which is why it isn't working.

Click to expand...

The 2nd switch works fine. Now that i've swapped the cables between switch 1 and the wall I can get it to work as I want.

There are two configs for nic cables so that may be the issue, plug the cable into the switch and a computer, I bet it works. Sounds like an old D-link cable

a switch and a router are very different. a router routes packets between networks and does not forward broadcast packets. a switch is kinda like a splitter but more efficient. once it learns what MAc address is attached to the ports it will forward those frames directly without blasting them out every port on the switch. old ethernet hubs do this.

do you have the cable between the two switches configured for trunking? are you using a crossover cable? what type of switches are you using? trunking and a crossover shouldnt be needed if you are using low end switches, not Cisco.
on the PC's behind the switch that isnt working, are they getting an IP address? are they getting a APIPA (169.254.0.1 to 169.254.255.254)?
what can you ping from those computers? can you ping the gateway? what do you see if you type in ipconfig /all in dos prompt?