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by r. a. caluste 1 view

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Cable from a 3com 10 mbps hub (service unit from my supplier) to a pc. cable length is only a few meters long. (media for network card is set to autoselect). has tcp/ip installed, client for microsoft networks and file and print sharing. passed the cable tester. connection was detected by win2k. once connected to pc, cannot ping pc on the same subnet. request timed out for ping. weird. what could be the problem?

35 replies

by grant maw

Have you tried setting the network card to 10Mbps instead of auto-detect? In some cases - especially with older equipment - this can help in cases like this.

HTH

by r. a. caluste

Have done it, still cannot ping. Connection was detected but still cannot ping. Anyways, I re-cabled and everything went well. Still I cannot figure out what went wrong with the other one.

by lizzy

Grant is correct. I have seen this with SMC cards. Your connection will only be as fast as your slowest component and you said the hub is only 10mbps. In addition to manually setting the card to 10mbps full duplex, I have had to sometimes reboot the pc not once but twice to get this to work properly. Good luck.

by r. a. caluste

Same comment as above (in addition to rebooting many times). Question is still open. However, the question now is:

If the cable passed the cable tester test (Im using Alantek Comm.), and the network components properly set up (network adapter, protocols) and configured, what are the reasons for not being able to PING another computer in the same subnet?

Like I have said above, i changed the cable and it worked fine but both cables passed the cable tester. weird.

by nettek

Since your network card is set to autoselect, I am assuming it has seperate 10 and 100mb lights on the card to tell you that you are connected. Is the 10mb light lit, and is the light on the hub for that port lit? If not, then either the network card is bad, the card is not seeing the hub, or the hub is not seeing the card.
Can you ping the loop back (127.0.0.1)? If not, then TCP/IP is corrupted and should be removed, reboot, and then reinstall.
Can you ping the IP address of the card? If you cannot, then there is a problem with the card or with the TCP/IP stack.

by r. a. caluste

Both leds are lit, and the card is seeing the hub. Can ping loop back and can ping ip address of card. See above comment.

by gigelul

You said that you change the cable and all was ok.
Where can be the problem?
Your tester or a bad contact (NIC or HUB).

by r. a. caluste

I dont think the tester is bad, it has been reliable ever since. I had the cable recrimped at both ends and swapped port in the hub (into a port which i know is working) but still couldnt get a successful ping.

by lizzy

Have you tried another NIC in that PC? I have had one that could ping both the loop back address and it's own card, but the NIC was "open" when receiving from the network--could send but not receive, therefore, saw it at the hub. Replacing the NICwith a known good one fixed the trouble. Pinging the addresses you mentioned does indeed tell you that the TCP\IP is configured properly on the PC. Also, make sure that you are indeed in the correct workgroup or domain (typos, etc.--just in case).

by lizzy

To be a little more clear about being able to see the cabled PC in question at the hub, because I could send fine on the one I was talking about, I could see a light at the hub when it was connected via patch cables. I, too, knew that the cable wasfine as I used it to set up other imaged PC's that had exactly the same hardware. I could see one light, but not two on the on board 3COM NIC on this new Dell PC. What I was seeing was data being sent, but the data that should be coming back or received was not making it and I had no second light on the NIC. Dell was trying to tell me my image was bad, but I had used the same exact image for 8 other PC's!! When I finally got them to come out and replace the MB, the contractor service man agreed with me when I showed him the equipment. You can ping other PC's on the LAN, but if it's not receiving or "open one side," you will not get a response back to let you know that it pinged. I really doubt that it's your cable if it works with other systems. It's got to be the NIC.

by lizzy

Seattle Guy is correct--should not have said full duplex. Autonegotiate can cause the problems he has described and setting it to just 10mbps (NOT full duplex) will probably help...

by eric_clemens

Seems obvious with the things you have tried that it is not a cabling issue. What OS are you running at the server and workstation? Are other PCs connected to this network having the same problem? (if yes, then it is the server or hub)

Other things to consider:
1) If this is the only computer, try using a cross connect cable to connect the PCs NIC directly into the Server NIC. (maybe the hub is bad)

2) You have MS networking installed, are you able to log in successfully and access resources on the server? (if yes, you have a protocol configuration issue on the server) What other protocols do you have enabled?

3) Are you using DHCP? If you have DHCP enabled with a subset of IP addresses, and your workstation is set to static (using one of those addresses), the server may be freaking out because it didn't lease that IP to the machine using it.

by r. a. caluste

all others pcs have no problem.

1) tried using the cross connect cable but the connection is not detected.

2) cannot log in because i cannot even ping remote server. can ping self ip and loopback so i think protocol is ok.

3) dhcp cannot becontacted, workstation is set to obtain ip dynamically.

I need answer to the question: how come i cannot ping remote server when using cable A, but things are ok when using cable B, when cable A and cable B both passed the cable tester test and led lights for both the network adapter nic and hub nic are on for both cables (A and B)?

by eric_clemens

Is the cable that isn't working sitting in a bucket of water?

I would remove it from the water.

Good luck solving this mystery.

by gigelul

I try to find some specifications about your tester. Nothing. Maybe your tester don't perform all necessary tests (impedance, resistivity, etc).
Test your cable with other tester (maybe a friend or your equipment vendor have other model).
About recrimpe the cable. You change connectors or simple recrimped the old? Try to change these connectors.

by otl

I am not familiar with the cable tester you are using weather it checks polarity on the individual circuit pairs or not. Or if you tried testing with the cable in the same position as it would be in if plugged into the computer (bad wire only in that position, connects in any other).

Your comment, " I had the cable recrimped at both ends and swapped port in the hub (into a port which i know is working)" brings to mind the important question " recrimped or replaced the ends?" If using another cable lets the computer operate normally then there are several possibilities of what could be wrong with that particular cable, below in order of what I have seen.

1. Bad connection between the cable and connector (one or more cable conductor(s) is not fully seated to the connector)

2. Replacing the cable caused rerouting the cable and eliminated RFI (interference).

3. Connector is damaged and forces wire contact away from pin on cable connection.

4. Reversed cable pairs in the connector.

5. Bad wire in the cable.

To attempt to identify the offender, ohm out each connection end-to-end using a multi-meter, even a $3-7 one will tell what is good and what is bad.

by tat4life

You may have your tcp/ip parameters wrong, check the subnet mask in thrtcp/ip properties to make sure you are on the same sub net as your other pc.

by tat4life

You may have your tcp/ip parameters wrong, check the subnet mask in the tcp/ip properties to make sure you are on the same sub net as your other pc.

by xgenius

If everything is fine after the cable change by itself then what is so hard to believe? Regardless if the cable passed power through it, it could be that there is enough of a flaw in the line that makes passing data packets impossible.
Having replaced so many damn cables that seemed as right as yours only to have the system work with a new one that was exactly the same leads me to say....let it go friend....

by cul8rm8e

please forgive my ignorance here. but are you in a workgroup enviroment? Domain, member of?

can you see any other machines in (my network places)? if not then check for (member of)in your properties of (my comp)network ID,

by johntech

One cable works another one doesn't, is that right ? Both pass testing ?

Is one wired as T568A and one wired as T568B ?

No that's not crossover its 2 different standards that will pass testing ?

by some guy in seattle

Answer 2 says that this is in full duplex. You can't run full duplex to a hub. If this is a managed hub, set it to *not* autonegotiate. Set your PC to 10Mbps and *half*-duplex.

And the same for the other equipment attached to this hub. (I'm assuming this is the case since you will need to ping something.)

Addendum to autonegotiation issue - I find that in many cases this can cause flapping, where one device will constantly try to negotiate different connections with the other device causing bad/intermittent/no performance. Statically setting it usually fixes this problem.

Hope that helps -

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