topic Re: Stange problem about ping in Operating System - HP-UX

Stange problem about ping

Kevin.Wang — Thu, 01 Jul 2004 03:03:13 GMT

HPUX L2000
I could not ping the HPUX machine from LAN this morning. but I can login the system from console. the network cable and NIC were proved to be good .
I wonder why I cannot ping the HPUX?

Re: Stange problem about ping

Keith Bevan_1 — Thu, 01 Jul 2004 03:14:50 GMT

Kevin,

The console is likely to be a direct connect via the console cable onto the LAN interface card and the ping will traverse across your network cable (probablty Cat5re) to your Lan interface card.

Are you able to check the status of the LEDs on the interface card ?

When you logged in via the console did you check the /var/adm/message & /var/adm/syslog/syslog.log files for error messages that might pertain to the lan interface card.

Is there an attention light on the front of the server and if its is on/flashing have you gone through the gsp logs ?

Just some ideas of things to check and rule out!

Keith

Re: Stange problem about ping

Victor BERRIDGE — Thu, 01 Jul 2004 03:15:47 GMT

Hi,
Can you ping the loopback from the console?
If so, can you ping from the console another box on the same net/subnet?

It could be many things, If you can ping the loopback but not the rest, try to stop nfs services and /sbin/init.d/net stop/start and see if that solves, it doesnt explain why though

Good luck
Victor

Re: Stange problem about ping

Victor BERRIDGE — Thu, 01 Jul 2004 03:20:43 GMT

Now if you can ping and telnet from the box to the rest of your world, How do you ping? using hostname? IP?, Do they match with what you see at the console? If using DNS has anyone changed the tables?

All the best
Victor

Re: Stange problem about ping

Kevin.Wang — Thu, 01 Jul 2004 03:46:26 GMT

I can ping loopback & its own ip address from console. but from LAN,i cannot ping the HPUX ,And can not telnet the HPUX from LAN.

And I cannot find any error from syslog,the light on the front of the server is normal and after I enter GSP, No error log.

Re: Stange problem about ping

Mark Grant — Thu, 01 Jul 2004 03:50:12 GMT

Is routing a possibility? However, I would suspect your lan switches/bridges rather than the HPUX machine.

Re: Stange problem about ping

Sanjay Kumar Suri — Thu, 01 Jul 2004 03:50:45 GMT

Check this link:

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=178307

sks

Re: Stange problem about ping

Victor BERRIDGE — Thu, 01 Jul 2004 03:53:47 GMT

Ok,
But as I asked already what about the box side? from the console what can you ping? other boxes on the same subnet? plugged to the same switch?

Re: Stange problem about ping

Kevin.Wang — Thu, 01 Jul 2004 04:07:06 GMT

in LAN,no VLAN,All machine are in one subnet.

Re: Stange problem about ping

Kevin.Wang — Thu, 01 Jul 2004 04:09:35 GMT

no DNS,no DHCP,I assign the machine a static ip address. and I ping the ip address not hostname of HPUX from LAN.

Re: Stange problem about ping

Mark Grant — Thu, 01 Jul 2004 04:12:18 GMT

Well, have you tried a "traceroute" to the machine to see what is happening to the packets.

Also, do you get an error when you "telnet" to the machine. If it just never gets a connection I would increase my suspicion about routing (either on the box or on the switches) or possibly start to wonder if someone had put up a firewall somewhere.

Re: Stange problem about ping

Bharat Katkar — Thu, 01 Jul 2004 04:19:42 GMT

Hi,
Check your network Cable ( Patch Cord ) of the LAn Interface for any loose connection or cable being bad or even the I/O outlet if you have any gone bad.
Hope that helps.
Regards,

Re: Stange problem about ping

Victor BERRIDGE — Thu, 01 Jul 2004 04:20:15 GMT

Hi,
What do you see from when at the console you type netstat -rn?
Has you lan the correct IP addr?
Is your lan up?

All the best
Victor

Re: Stange problem about ping

SAHA — Thu, 01 Jul 2004 05:42:30 GMT

Things looks like:
1.Is autonegotiate on (Speed) ...if yes fix the spped with lanadm.
2.Otherwise it looks like fauly network card, patch cord, switch, hub router etc.
Will it possible to swap patch cord from a known good mc/s ..

Thnaks,

Re: Stange problem about ping

Fabio Ettore — Thu, 01 Jul 2004 08:31:41 GMT

Hi,

I saw a similar problem where ping went in fault due to bad system configuration.

If you have not DNS then check that /etc/resolv.conf doesn't exist. Check /etc/nsswitch.conf; if exists it should contain a line with

hosts: files

Then check /etc/hosts too.

Another reason could be a corrupted /etc/hosts.
Then check it for errors and try

# mv /etc/hosts /tmp/hosts.old
# cp /usr/newconfig/etc/hosts /etc

Modify it with good entries.

HTH.

Best regards,
Ettore

Re: Stange problem about ping

Kevin.Wang — Thu, 01 Jul 2004 20:01:45 GMT

#ifconfig lan0 down
#ifconfig lan0 up
The NIc is up.
and no firewall,the network configurataion is OK,such as ip address,netmask and default gateway.

I have to restart the HPUX,after the boot completed,everything is OK. Who can tell me why i cannot ping before the HPUX boot?

Re: Stange problem about ping

rick jones — Thu, 01 Jul 2004 22:32:59 GMT

Culd be any number of reasons you could not ping before the reboot - perhaps someone altered the network settings by hand and got them wrong. Perhaps you have a router that does not respond to ICMP Echo requests (pings) and the gateway got marked as down (set ip_ire_gw_probe to zero in the nddconf file.

Next time, when things go wrong, if you have other HP-UX systems on the same switch/network segment, you could try the linkloop(1m) command to check link-level connectivity, before moving up to stuff like ping and telnet.

Re: Stange problem about ping

Victor BERRIDGE — Fri, 02 Jul 2004 03:07:48 GMT

I once had the case when the IP stack got corrupted...

All the best
Victor

Re: Stange problem about ping

Kevin.Wang — Fri, 02 Jul 2004 03:15:21 GMT

To Victor Berridge
Why the IP stack got corrupted?and how did you fix it?

Re: Stange problem about ping

Fabio Ettore — Fri, 02 Jul 2004 03:57:54 GMT

Hi Kevin,

reasons for IP stack corrupted or 'something else' corrupted are some.
I think bad installation of patches or powerfail or suddenly interrupt operations vs. a device. Every one would deserve many words.

Anyway hypothesis more believable of your problem is what rick said about change of network settings (routing or something else) run-time. For a better explaination of 'run-time' I am going to give you an example:

- change routing table:
# route add net X.X.X.X ....

but if you don't modify /etc/rc.config.d/netconf the command above will be deleted after reboot.

HTH.

Best regards,
Fabio