topic Re: network connectivity problem in Operating System - HP-UX

network connectivity problem

Edgar_8 — Thu, 04 Dec 2003 04:51:47 GMT

Hi,

We have completed an HP-UX 11i install but the server fails to be seen/connect on the network. The IP;Gateway ; subnetmask is correct in the netconf files but still no connectivity. The server has 2 NICs:
lan1 - ethernet 10/100bt
lan2 - gigabit 1000

Any possible reasons for network connectivity connection problems?

Thanks!

Re: network connectivity problem

Mark Grant — Thu, 04 Dec 2003 04:56:10 GMT

One "gotcha" that I see quite a lot on new installs with multiple lan cards is when the network cable is in the wrong card and therefore the patching is wrong.

However, assuming the cable is OK then check routing "netstat -rn"

Also, try and ping "localhost" to make sure that there is no fundamental tcp problem.

Re: network connectivity problem

Rajeev Shukla — Thu, 04 Dec 2003 05:02:42 GMT

Hi,
Login to the console of the server, do a netstat -in and see that you have right IP address assigned to the lan interfaces, i mean to see if the cables are pluged in right network for the respective interfaces. Ping the local host, ping the gateway, if none work, try low level ping which is linkloop. Which works on the MAC level, have a look at the man pages of linkloop and try pinging other interfaces...
By the way first verify you have link lights glowing on the interfaces on the server.

Re: network connectivity problem

Sunil Sharma_1 — Thu, 04 Dec 2003 05:29:22 GMT

Hi,

why don't you use linklook to check H/W level connectivity?

for more info check man linkloop

Sunil

Re: network connectivity problem

Edgar_8 — Thu, 04 Dec 2003 06:59:08 GMT

Hi,

If we ping the localhost we get a reply, but any server on the network cant be reached,including the default gateway! All the cables are connected & netconf is set-up correct. Any ideas would be most appreciated!

Re: network connectivity problem

Zigor Buruaga — Thu, 04 Dec 2003 07:57:52 GMT

Hi,

Run "netstat -in" and see if there is any asterisk near the interfaces name.
Check also with "ifconfig lanX" ( where X is 0,1, etc ) that the interfaces are up and correctly configured. For example when I run "ifconfig lan1" I see:
lan1: flags=843

Try also, as suggested, with "linkloop":
# linkloop -v 0x"nic_mac_address"
( You can go to other HP-UX server and run "lanscan". In the output you will see the column "Station Address", use that value ( i.e. 0x08000930A4B4 ) in the linkloop command ).

HTH
Kind regards,
Zigor

Re: network connectivity problem

Fabio Ettore — Thu, 04 Dec 2003 08:06:12 GMT

Hi Edgar,

what is IP address of your system and gateway configured in netconf?
I aks you this question because if they are not on the same subnet then problem could be that.

Just a thought...

Best regards,
Ettore

Re: network connectivity problem

Ron Kinner — Thu, 04 Dec 2003 09:50:41 GMT

Pinging your own IP proves nothing since the box will recognize it and never send it out on the wire. Instead try:

lanadmin
lan
display

first couple of line will tell you if the NIC is properly programmed and if it is working. You should see two UPs. Disconnect the network cable to verify you are looking at the one you think you are. You should lose one of your UPs.

ppa 1
or maybe ppa 2
depending upon what the first display showed for ppa (+1) will let you run display on the second NIC.

You can also try
lanscan

linkloop is a good test for level 2 connectivity but can only be trusted with other HP hosts. You must specify which interface to use since you have two.

linkloop [-i PPA] [-n count] [-r rif] [-s size] [-t timeout] [-v] linkaddr ...

If your IP address is the first or last subnet then turn off subnet checking in ndd.

ndd -set /dev/ip ip_check_subnet_addr 0

will do it for now but you need to put it in nddconf in order for it to be remembered at boot.

edit /etc/rc.config.d/nddconf to add:

TRANSPORT_NAME[0]=ip
NDD_NAME[0]=ip_check_subnet_addr
NDD_VALUE[0]=0

If there is already an entry then you have to change the numbers in brackets to the next higher number.

If your gateway does not want to answer pings then turn off dead gateway detection with ndd.

ndd -set /dev/ip ip_ire_gw_probe 0

Also add the entries into /etc/rc.config.d/nddconf file to permanently disable dead gateway detection.

TRANSPORT_NAME[1]=ip
NDD_NAME[1]=ip_ire_gw_probe
NDD_VALUE[1]=0

You may have to remove the gateway and reenter it to get it out of dead status.

Ron