[Ponch]

Hi, we've had several cases the last few months of computers losing network connection. The cable appears plugged in but the little yellow triangle says "limited or no connectivity" (or something like that). Reseting the cable at both ends or restarting the PC doesn't change anything, the computer doesn't get any IP from the DHCP and cannot ping anything. All appears correct in the NIC's properties (well, nothing has been changed either). I've found out now that pulling the power plug on the PC solves the problem. So my question is... is it possible that a problem in the network plug or at the other end (hub ?) "blocks" the NIC untill hard reset or does this look like a hardware problem ? Anybody had that ?

[tain]

Rebooting has no effect yet pulling the PC power fixes it? That is uncommon in my experience, and could indicate bad NIC(s). Has the office had power supply issues recently?

Quote

So my question is... is it possible that a problem in the network plug or at the other end (hub ?) "blocks" the NIC untill hard reset or does this look like a hardware problem ? Anybody had that ?

Check the DHCP server logs. Try swapping in a known-good switch/hub.

[DigeratiPrime]

Is this an onboard NIC, aka LOM, or is it a discreet card and in that case PCI or PCI-e? What is the controller and driver revision?

If it is onboard also tell us the motherboard model and bios revision; and try updating the bios.

Your device may not be sending out the gratuitous arp, unless its a cold boot, and hence not pulling an ip from the dhcp server.

[anthonyaudi]

On some cards theres a function called shut down to save power or something like that in the card properties (it is very unlikely that is the problem) but try unchecking that if it is checked off.

Also (shot in the dark here) but are your IP's manually assigned in the tcp/ip settings?

[cluberti]

Power cycling a system and the NIC still doesn't work.... did I read that right? If it takes an actual hard power reset, then I would claim faulty hardware for sure.

[Tripredacus]

First thing is to do a manual renew. Hopefully you will get another error than a DHCP timeout. If you do get a DHCP timeout, do an ipconfig -all and verify your MAC address (hardware address) is not all Fs. Also verify that the NIC shows up in there, and that you don't have any Network Bridges in Network Connections.

Try this out
1. open your command prompt (cmd.exe)
2. type 'ipconfig -release'. Ignore what it says
3. type 'arp -d' and ignore what it says.
4. restart the computer
5. when it comes back up, go into your cmd.exe again
6. type 'ipconfig -all' and post what it says here.
7. type 'ipconfig -renew' and post what error it gives you.

Also go into Network Connections and tell us what icons you have in there. Its not important to know if its firewalled, connected, etc.

Results
1. If it says DHCP timeout, you may either have a failing NIC (not totally dead) or a corrupted TCP/IP stack
2. If you receive any other error, such as (but not limited to): "operation was attempted on an object that is not a socket" or "access denied" or "cannot find the file specified" these can be researched and resolved fairly quickly.
3. If your NIC is bridged with something, you will not get an IP.
4. If you have a cable or dsl modem, make sure to power it off after you release the ip and power it back on when you restart the computer.