SNMP Traps problems when removing LAN cables

[Victoria Leung]

Hi,

I have a HP A400 box (HP-UX 11.0) with 2 LAN cards. They are configured to 2 different LAN segments. LAN0 is connected to a Cisco switch and LAN1 is directly connected to a HPOV SNMP server. "SNMP GET" and "SNMP RESPONSE" seems working between A400 and HPOV except that when I pull out the cable between LAN0 and the switch, there is no SNMP traps send out to HPOV.

"Trpdstagt" daemon is already running and the configuration file "snmpd.conf" is OK.

Should there be any traps send out in this case?

[Uffe Gavnholt_1]

Hi Victoria,

There are two sides of the story, one of them is the configuration on your OV server.

If you during normal operation can receive traps from the server, the Management server is most likely the place to look for this.

I assume you are running OV NNM, if so, the default SNMP traps are NOT displayed in the alarms browser.

Go to "Event configuration" under "options", look under enterprise SNMP traps - and verify that the link down trap is set to diaplay in some category.

If you have some HP mibs loaded, you might want to create your own default SNMP trap definitions, by choosing a generic event ID.

Hope this helps

Uffe

[Victoria Leung]

Hi Uffe,

Thanks for your reply!

We have other HP Aclass boxes with similar network configurations as the A400 box, but we can receive traps in the OV NNM for the same case. So I think it is not problem in the OV.

It seems that the A400 has not sent out any traps to the OV. Is there any sniffer command like "snoop" in HP-UX that I can use to see if any traps has been sent out in the A400 box?

Victoria

[Uffe Gavnholt_1]

Hi Victoria,

To trace net traffic from a HPUX box, you can use the command "nettl".

just to make sure, can u ping the system, when lan0 is disconnected?

Other thing is whether or not routing is an issue - are the management station, and the server on the same IP network?

third the netmon process on the management system, will try to add it self to the list of trap recipients - try browsing the mib of the server, to see which IP address it has registered itself as - could be the other interface on the management station.

Last thing is that you can enable trap debugging on the pmd process on NNM - by modifying it's LRF file - this dump file would show you clearly if anything is received by the management station or not

that's all i got ;)

Uffe

[Victoria Leung]

Hi Uffe,

Thanks again for your help!

Yes, when I pull out the cable in lan0 of the A400, I can still ping the IP address of lan0. That is not the case in our Aclass server. I think the A400 shouldn't be correct. But I have already check my /etc/rc.config.d/netconf. It's already the same and I don't know what's the problem in the A400.

Have you got any ideas on why I can still ping the interface? Does it lead to the problem that the A400 cannot send out traps?

Thank you again!

Victoria

[Uffe Gavnholt_1]

It might matter...

If NNM still is able to ping the system, the Interface might be reported as being down, but the system wont.

That means that you will be able to see the interface when you open the server symbol on a NNM map. (after polling the server from the fault menu)

The ifDown event that NNM generates by itself, is not displayed in the alarmbrowser (you can make it by configuring the event OV_IF_Down to display in a category).

It would help I think if you can tell me a little more of what you want NNM to perform, when the interface goes down.

[Victoria Leung]

Hi Uffe,

I am sorry for the misleading. When the cable connected to lan0 of A400 is pulled out, I can still ping the interface lan0 from A400. It seems that the interface turned into its loopback interface.

NNM cannot ping lan0 of A400 in any case since there is no routing in NNM to A400 lan0 through A400 lan1.

I suppose that a A400 lan0 LINK DOWN trap will be sent to the NNM through A400 lan1 interface, so that the NNM can generate an alarm on that. However, this is not the case, no traps can be received by the NNM.

Thanks for your help!