General discussion

Locked

NIC will not connect to the internet

By crazedave ·
I work with about 100 PC's and have been having a problem with the NIC's for about 6 months now. It happens with the 3com or Compaq cards, with older PC's and newer one's.
What happens is the PC can not connnect to the internet, but all other network related resoures are still available. There doesn't seem to be any reason for the sudden loss of the internet connection. This has happened to about 20 or 30 PC's and the only way I have been able to resolve the issue so far is to replace the NIC with another one. The replacement could be a NIC that was replaced for the same reason in another PC.
I have tried reinstalling the service pack, removing the networking and reinstalling it, upgrading to IE 5.5, and recently have set the lease on IP addresses to expire every 14 days instead of the 10 days it was at.
I'm not sure what else to try and would appreciate any help on this.

This conversation is currently closed to new comments.

5 total posts (Page 1 of 1)  
| Thread display: Collapse - | Expand +

All Comments

Collapse -

NIC will not connect to the internet

by Stillatit In reply to NIC will not connect to t ...

I suspect a problem with your DHCP server giving out some bad information.

When you next hit one of these problems, check the IP, mask and gateway. A mask or gateway problem will have these symptoms. An incorrect setting in your firewall could also do this.

Incorrect network mask: There are two parts to this, the DHCP server and the router. Check the range of addresses which your DHCP server is handing out, and make sure that the range is reasonable, that the mask does not cut off any of the range, and that the default gateway is on the same segment as the range (but excluded from the range).

Gateway router: Make sure that the router knows its own LAN (inside) address and is using the correct mask. If the mask is wrong the router might think it is getting traffic from an incorrect segment (and ignore it).

Firewall: If you allow traffic through your firewall based on IP, an incorrect mask might cause the firewall to see some stations outside of the "allowed" range. In this case you will see the "bad" address grouping.

If you have more than one network segment, make sure that stations on each are getting addresses, masks and gateways appropriate to their own segment.

If you are using more than one DHCP server, check the settings in each. It may be that anyone getting an address from the "bad" server has a problem.

If any of these are the cause, the reason an old card works is that its MAC address has been "forgotten" by whichever server gave it bad information, so it broadcasts for a new server, which hopefully gives it good information.

Good luck.

Collapse -

NIC will not connect to the internet

by crazedave In reply to NIC will not connect to t ...

I think I figured that the problem is with our firewall. We can now reset the firewall to resolve this problem for the person or persons affected that day, so there is something incorrectly setup in the firewall, which I am going to look into next week. I appreciate the answer in trying to help.

Thanks,
David

Collapse -

NIC will not connect to the internet

by tbradley In reply to NIC will not connect to t ...

This answer assumes the "other" network resources are login, shared files, and printers ( non-tcp/ip ).

Run winipcfg at the command prompt
(start-run), and see if the TCP/IP numbers
are "skewed", that is, your subnet mask is set to 255.0.0.0 and the IP number is in the 192.0 range vice the 10.xxx.xxx.xxx.

If this is the case, the card is not grabbing an IP number from the DHCP server, and is loading an internal default. Other network protocols still work however.

The only way I have found to defeat this loop is to deltete the card in Network Neighborhook and in system, and then boot the computer into dos mode. Run the card configuration utility, ie 3c5x9cfg for 509 cards, 3c90x.cfg.exe for 905 cards, and set the media select manually to either 10mps or 100mps, depending on your equipment, and half duplex. REboot, and re-install the card.

I've been having the same problem mostly with the 3c905C cards and 3com Switch 1100's but it's happened with other configurations also.

3com has not been good about helping, but the non-technical explanation I've been able to glean is that the network has taken some sort of a power surge, and the switch port and the card have gone into a "auto-negotiation" loop. You have to force the card out of this mode by the config utility, and I've had to change the port its attached to also. Put in a different adapter with a new mac address, and the problem goes away.

e-mail me direct if you need some more specifics.

Collapse -

NIC will not connect to the internet

by crazedave In reply to NIC will not connect to t ...

I think I figured that the problem is with our firewall. We can now reset the firewall to resolve this problem for the person or persons affected that day, so there is something incorrectly setup in the firewall, which I am going to look into next week. I appreciate the answer in trying to help.

Thanks,
David

Collapse -

NIC will not connect to the internet

by crazedave In reply to NIC will not connect to t ...

This question was closed by the author

Back to Hardware Forum
5 total posts (Page 1 of 1)  

Related Discussions

Related Forums