Keep loosing network Connectivity

[John Love_3]

I keep loosing network connectivity with an A class box.
After i reboot it, then i have no problem for some random amount of time. In this case, 24hrs.
I cannot ping the server, it cannot ping anything except localhost and it's 208.X.X.X address.
Any ideas? Why does it stop working?
Thanks,
John

[someone_4]

what happends if you run
lanadmin
and check for errors?
And then reset the card though lanadmin?

We had that happend to one of our a class servers and it would work if we reset the card though the lanadmin. We ended up having to replace the nic card.

Richard

[Craig Rants]

Is the a box a 11.00? Can you ping the default gateway from the A box when it is up?

If you can't ping it, you have what is called dead gateway detection, basically if you can't ping the gateway, then hpux sees the gateway as dead and will not route packets to it.

There is a ndd patch for this, or if you have your network admin allow icmp, that should fix it.

Ofcourse this may not be your solution, just what popped into my head.

GL,
C

[John Love_3]

OK, the lanadmin showed a lot of errors on one machine.

I actually have 2 a D380 and an A. Both have 11i (11.11).

The A-box had lots of errors and the reset fixed my connectivity (for now). What would that be?

The D box didn't have many errors but showed it was Administratively UP and operationally DOWN. It had a ton of Carrier Sense errors. is that a cable problem?

Thanks.

[John Love_3]

I forgot to add that I can ping the gateway when it's working. I can ping everything when it's working and nothing when it's broken.

[Darrell Allen]

Hi John,

Have you verified the NIC and switch both have the same duplex setting? Ideally, I'd force the speed and duplex settings at both ends and turn off auto-negiotiating as it often fails to work correctly.

Darrell

[John Love_3]

I haven't forced, the duplex/speed, but have several other boxes with no problems. Perhaps I've just been lucky.

I'll try it.

[Bill Hassell]

Unless you have massively long cables or very badly routed cables, a 100 Mbit LAN won't have any errors. Therefore, the errors are very likely due to auto-negotiation failing between the LAN card and your switch. Note that cables between specific lengths can also cause autonegotiation errors.

When autonegotiation fails, the standard says to revert to half-duplex. However, the switch may not follow and will continue sending full duplex packets, causing massive errors. Many switches will then disable the port due to errors. Use lanadmin -x to display the duplex setting. When you set the card to manual (ie, 100 FullDuplex), that setting MUST be duplicated on the switch or the same failure may occur on the switch side.

Another tool to track down where a network connection fails is to use traceroute, but if it fails before reaching the gateway/router, then the problem is likely between the computer and the switch.

[John Love_3]

Bill, et al.
Both boxes were set to Auto Neg. and so was the switch ports they were in.

I've forced both the switch ports and the servers to 100FD, we'll see what happens.

I guess my D box was 100 HD for some reason. Also it took me a few to figure out it is using PPA1 not PPA0.

Thanks for your help.

I'll assign you points tomorrow Bill. (let's see the outcome! :)

[John Love_3]

Well, my D class works great, but I'm still having problems with the A box.

I forced the switch port and lan card to 100 FD, but this morning I'm unable to ping or telnet to the A box.

Any other Ideas????

John