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Strange behavior of interface lan0

Alex_133
Advisor

Strange behavior of interface lan0

We have a 9000/778/B180L(11.00) workstation where we recently replace its faulty mainbord, all the configuration remains same as we use back the original harddisk without reinstalling the OS.

Then we experince strange behavior of the lan0, for example: No other machine is able to ping this machine, but this machine is able to ping everyone.

When this machine establish a connection with some other machine(e.g. Telent/FTP session), then everyone is able to ping it.

I suspect when no TCP/UDP session is establish with other nodes, the OS will bring down the lan0, this may not be the case at all...

Anyone has experience this before?
14 REPLIES
Mihails Nikitins
Super Advisor

Re: Strange behavior of interface lan0

Hi,

Looks strange...

You can check lan0 status at any moment by command
ifconfig lan0
I doubt it goes up and down...

Can you ping the host from itself (both loopback and public addresses)? Do you use DHCP for this workstation?

Do you ping the workstation from other hosts by IP address or by name? Try IP addresses first to be sure there are no problems with naming services.

BR,
Mihails
KISS - Keep It Simple Stupid
Alex_133
Advisor

Re: Strange behavior of interface lan0

Sorry, this is a duplicate post.
Alex_133
Advisor

Re: Strange behavior of interface lan0

....and shouldn't be under [databases] catagory, sorry again.
curt larson_1
Honored Contributor

Re: Strange behavior of interface lan0

in your network configuration files are you still using the MAC address of the old lan interface?
G. Vrijhoeven
Honored Contributor

Re: Strange behavior of interface lan0

Hi,

check out the speed and duplex settings on the card and on the switch. You can use lanscan to check the ppa number and lanadmin -x ppa ( ux 11) to display the settings on unix.

use lanadmin -X 10fd/10hd 100fd/100hd ppa to set the interface in the correct settings (100fd is prefered if possible.)

If these settings are correct check the netmask. (ifconfig lan0) settings


Gideon
Paula J Frazer-Campbell
Honored Contributor

Re: Strange behavior of interface lan0

Alex

If fine before the motherboard change then suspect the seating of the lan card.
Down the machine and remove and refit the card several times to clean the contacts.


Paula
If you can spell SysAdmin then you is one - anon
Ikuo Fukuda
Occasional Advisor

Re: Strange behavior of interface lan0

Hi alex.
Do you have same IP address host in your local lan?

Eat everything like a pacman.
Alex_133
Advisor

Re: Strange behavior of interface lan0

Unfortunately, setting the lan0 to FULL DUPLEX didn't solve the problem. Also, the MAC address is not configured in the /etc/rc.conifg.d/hpbase100conf or /etc/rc.conifg.d/hpetherconf

We can isolate the problem from duplicate IP, DNS, cable or routers, because as long as I establish a TCP(e.g. telnet) to another node in the LAN, the others start getting PING response from this machine, whenever I terminate the session, then the others start having PING timeout.

rick jones
Honored Contributor

Re: Strange behavior of interface lan0

Actually, you may still have some duplicate IP or duplicate MAC issues.

When a TCP connection is established, the system will ARP for the remote IP address to MAC mapping. This is a broadcast and all the nodes in the broadcast domain will see it and update their IP-MAC mappings for the node. If they had a different MAC before, they would have been sending their pings to some other system which may have been silently discarding them or something.

So, as a triple check, examing the arp caches on the remote systems while you go through all those steps you mentioned, and see if the MAC addresses are as they should be.
there is no rest for the wicked yet the virtuous have no pillows
Alex_133
Advisor

Re: Strange behavior of interface lan0

Other node in the LAN are having the same MAC with the HP-UX machine, which is 0:10:83:b8:1b:cb

By checking tcpdump, I can see that there are constantly arp request/reply in/out from this machine, the MAC is updated.

Besides arp, there are other activity like netbios, dsn query, etc. Everything just seems fine from inside. I wonder why...



Eugeny Brychkov
Honored Contributor

Re: Strange behavior of interface lan0

Very good, Alex. Now you know that another node has the same MAC address... so you can simply set MAC address up in the hpetherconf file to another value so it will take over workstation original LAN MAC address and this way you'll solve this conflict. BTW, if another conflicting machine is hpux one, check this hpetherconf there. Maybe you simply need to remove MAC address from that file?
Eugeny
Eugeny Brychkov
Honored Contributor

Re: Strange behavior of interface lan0

Alex, this MAC address you mentioned "0:10:83:b8:1b:cb" is strange for B180L. First 3 bytes should be "08:00:09" - this is HP identifier (manufacturer's identifier). Check what your PDC says about station LAN address. If it shows same address, please call HP to check if this address ("00:10:83") is valid for B180L. BTW, is this LAN card you're talking about is ADD-ON card or motherboard built-in?
Eugeny
rick jones
Honored Contributor

Re: Strange behavior of interface lan0

Duplicate MACs is why one should almost never hard-code the MAC address in the "etherconf" config file for a link, and _NEVER_ use dd to clone boot discs...

As far as 080009 goes, that hasn't been the UPC on links from HP in _years_ I forget if it was that we exhausted that space, or simply started getting different MACs when we started OEMing NICs from other manufacturers.
there is no rest for the wicked yet the virtuous have no pillows
Eugeny Brychkov
Honored Contributor

Re: Strange behavior of interface lan0

Patch your machine with latest GR and HW enablement patch bundles. This may help
Eugeny