Network Problems

[iago]

I suspect this is a case of hardware failure, but I'd like to make sure.

I plugged my laptop into my hub at work that I always use, and I can do the dhcp just fine (I get my good ol' ip address), but after that, I can't connect to any other computer (on or outside the network) on any port (ping to or from, http, etc).  Any idea what this can be?  I just find it weird that dhcpcd would work, but nothing else will.

Thanks!

[Adron]

Can you ping the dhcp server? Might you be firewalled? Some local firewall that drops all packets?

I don't see why dhcp would work and not other packets. A dhcp request should be similar to a ping - short packet and short reply. Do you have access to packet capturing on both sides of the hub? Do you see activity on the lights?

Some time I've had a cable with a bad connection where it could transmit so-so, single-duplex. That could cause problems a bit like what you're describing, a packet would get through now and then, but when there was a lot of traffic it would just break down.

[iago]

I can't ping 192.168.1.1, and I *think* that's the dhcp server, but I'm not entirly sure.  

When I ping, the light on my hub DOES blink, butr I still get "Destination Host Unreachable" for everything.  The odd thing is, my hub is sitting *right here*.  I can 3 plugs in it, one goes to my desktop (*waves*), one goes to my laptop, and one goes to the wall.  My desktop is fine, but can't ping my laptop, my laptop can't ping anything.

[Adron]

Run ethereal in promiscous mode on your desktop and see if you see the pings from your laptop. Run ethereal on your laptop in promiscous mode on your laptop and see if you get the pings from your desktop. It is a hub, right, not a switch?

Look at the link lights for your connection on *both* the hub and the laptop. If only one is on, you have a cable that is broken one way. Look for any unusual blinking too. Verify that your laptop isn't configured for full duplex if the hub doesn't support that, or reverse.

Running a full duplex connection to a hub will cause instant collisions 99% of the time, and crap network performance.

[iago]

Bah, I have to stop the radio to check lights

The laptop was working before, so I'm reasonably sure the configuration is correct.

I can't do ethereal on my desktop (I'm not an admin, it's a work computer) but I can try on my desktop.

When I ping my desktop with my laptop, the desktop/network lights blink, but the desktop light doesn't.

When I ping my laptop with my desktop, the desktop/network lights blink.

When I ping out from my laptop with ethereal going, only ARP goes out, "Who has 192...[desktop]? Tell 192..[me]" and nothing comes back.

My laptop with Ehtereal running doesn't see any network traffic to/from my desktop.

I tried changing the port on the hub that the laptop's plugged into with no avail.

[iago]

Also, when I'm not doing anything with my laptop, there is no constant light, but when I try to do something I get a blinking light.  The other two connections have blinking lights.

I also tried unplugging the hub.

[Adron]

Bah, I have to stop the radio to check lights

Have to stop the radio? You can't see the lights without moving things away?

The laptop was working before, so I'm reasonably sure the configuration is correct.

I'm not convinced that you're actually getting an ip from the dhcp server. Perhaps you're just keeping your old one (from a long lease), or perhaps you're getting one from microsoft's range.

Can you ethereal while doing ipconfig /renew and see that you're actually getting traffic from the dhcp server?

I can't do ethereal on my desktop (I'm not an admin, it's a work computer) but I can try on my desktop.

When I ping my desktop with my laptop, the desktop/network lights blink, but the desktop light doesn't.

When I ping my laptop with my desktop, the desktop/network lights blink.

I'm confused about your use of the word "desktop" here. Do you have a rx and a tx light on your desktop's network card? If so, can you see the rx light blink on your desktop when you ping from your laptop?

Can you see any hub lights blink when you ping from the laptop?

When I ping out from my laptop with ethereal going, only ARP goes out, "Who has 192...[desktop]? Tell 192..[me]" and nothing comes back.

My laptop with Ehtereal running doesn't see any network traffic to/from my desktop.

I tried changing the port on the hub that the laptop's plugged into with no avail.

Try reversing the cable between hub and laptop. If that doesn't allow you to receive (ethereal) data from the network on your laptop, it would seem like your network card in your laptop is broken. At least the receive line and possibly the transmit too.

Perhaps some connector isn't ok? I've had 3com pcmcia cards where the small cable from pcmcia connector to rj45 slot broke. They were pretty fragile.

[Adron]

Also, when I'm not doing anything with my laptop, there is no constant light, but when I try to do something I get a blinking light.  The other two connections have blinking lights.

I also tried unplugging the hub.

Is there no constant light on the other connections either?

There's typically a constant link light that goes on when the hub establishes a connection with the laptop. There are "link packets" being transmitted all the time just to keep the connection going, and when those are being received ok, the link lights go on at each end.

[iago]

Well with vL radio going, the light constantly blinks.

I should have mentioned I'm on linux, and "dhcpcd -d eth0" definately retries getting my ip.

When I say blinking lights, I always mean on the hub.

I get the exact same error after reversing the cable. Sounds like the NIC?  It's given me problems before but it's always worked at.. work.  I have a usb one, but it's at home.  I don't like the idea of going the full day with no network from laptop, but I guess I'll survive

[iago]

Also, when I'm not doing anything with my laptop, there is no constant light, but when I try to do something I get a blinking light.  The other two connections have blinking lights.

I also tried unplugging the hub.

Is there no constant light on the other connections either?

There's typically a constant link light that goes on when the hub establishes a connection with the laptop. There are "link packets" being transmitted all the time just to keep the connection going, and when those are being received ok, the link lights go on at each end.

Sorry, I meant that the 2 connectors have constant "Link" lights, but the laptop's one doesn't.  It just has the flickering Rx light when it tries to do stuff.

[Adron]

Sorry, I meant that the 2 connectors have constant "Link" lights, but the laptop's one doesn't.  It just has the flickering Rx light when it tries to do stuff.

If you don't get a Link light, that's a strong indication of a problem. The link light should go on as soon as the card is activated, whether it has an IP or not. Since you've changed the cable and the hub with no effect, it's now time to change your laptop

Have you ever had random problems before? It could be just a bent pin in the slot... But then, that would be likely to work a bit sometimes. Maybe you'll have to get a new nic for your laptop.

[iago]

Well, I know there's a screwed up pin.  You might remember I posted awhile ago about it.  But so far at work it has *never* given me a problem, I suspect it's because I'm using a straight cable instead of crossover.  I do have a USB one which I use at home, but I stopped bringing it when I realized it worked 100% here.  Well, till today

I guess is one of those, "You'll get over it" situations

[Adron]

Straight cable or crossover cable makes no difference. Which pin was it again?

edit: I vaguely recall you not wanting to open it up and resolder the pin... Maybe it's time to do that now

[iago]

Straight cable or crossover cable makes no difference. Which pin was it again?

edit: I vaguely recall you not wanting to open it up and resolder the pin... Maybe it's time to do that now

Or maybe it's time to start bringing my usb NIC with me

It's the first pin on the right:

Code Select Expand

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[Adron]

Or maybe it's time to start bringing my usb NIC with me

It's the first pin on the right:

Code Select Expand

|||||||\

The pins in use are 1, 2, 3 and 6 if i remember correctly. It seems that you've managed to bend pin 1. Hmm. I don't remember now, how badly bent was it? Might it have been making contact before and not now?