SCO

SCO unix 5.0.5 - Suddently network lost & has to be reboot. I try to stop TCP & start TCP. but no connection. Any idea about that.

thanks

The best results I've had in diagnosing network problems related to the NIC have been through the diagnostics provided by the card manufacturer and running under DOS. Using the diagnostics on 3Com stuff that I've standardized on requires a floppy and a DOS boot diskette but it could all be put on a CD if you have CD boot capability.

Dear Edfair,

I changed the NIC. also the same problem. we are using 3com 3c90b cards which is automatically detected by Unix. we have another server which is doing the same thing. When you lost the network you have to restart the server.

thanks

I can't recall the reason but I stopped using the 905B at some point and only install the 905-TX version, which has given good service. Or an earlier PCI based one, can't remember the type, and when all else fails I fall back to the 509 and the ISA bus.

You might try running the DOS based diagnostics and see if anything shows up but based on the multiple failures on that card I suspect that you would be better off getting the TX version.

What kind of system are you dealing with, hardware wise? Most of mine is PII based but I may have some PIII.

i am using intel Xeon 3.00ghz 2 processor pc's. i may try with tx NIC cards

thanks

I would suggest that perhaps you are running out of tcp connections or you have a bad nic on your network.

If you check scoadmin / network / tcp of the NIC you should see how many tcp connections you are willing to allow. We set up most machines to be 512 but you can set it up any way you like.

I have seen several times, SCO 5.0.x boxes that the network seems to just die randomly and upon reboot then it works flawlessly. Usually it is one of two things, either there is a bad NIC on your network that is corrupting arp packet requests (wireshark or another packet sniffer should show you this symptom within a few minutes, and will usually be miss-labeled "Gratuitous Arp Requests" and should be called "non-conforming arp requests") or you are having something make more socket connections that you have tcp connections. As soon as you reach the number you specified, the NIC will stop processing all traffic.

We check the network by using wireshark. there are plenty ip's giving Gratuitous Arp Requests. Do you have any idea to block these from UNIX servers. without shutting down lot of devices on the network.

thanks