No Route To Host

[Tony Martin_1]

I have recently attached a HP server to an existing network consisting of a single NT server and several NT 4 workstations.

Having updated the IP address of the HP Server to suite the local network (10.0.0.*) and entered a default route (set as the NT server machine on the local network) I recieve the following errors when attempting to ping (from the HP box).

1. If I attempt to ping the default gateway machine I recieve 'No Route To Host' errors.
2. If I attempt any other machine of the local network it simply reports 100% packet loss.

I isolated the HP server and connected a simple domestic gateway/firewall and set it as the default route destination. Doing this I could ping the device without problems.

At this stage I am becoming quite confused and would appreciate it greatly if someone could shed some more light on my problem(s).

Some background detail:

HP Server:
Hardware : 9000/847
OS : HP-UX A.9.04 D

Local Network :
IP Range 10.0.0.1 - 255
Netmask (on all machines) : 255.255.255.0

HP route table :
Destination Gateway Flags interface
127.0.0.1 127.0.0.1 UH lo0
default 10.0.0.2 U lan0

(10.0.0.2 is the address of the local NT Server instance and is the gateway address used by all Windows machines on the network)

Many thanks in advance.

[Michael Tully]

Hi,

A few things to note:

First is that HP-UX 9.x is not supported
anymore as it is not Year 2000 compliant.
In saying that you seem to have a routing
problem. You must set the system default
route to your router, not to an NT server.

To set up a temporary route do this:
# route add default 10.0.0.x 1

The IP address is that of the router on
the same subnet. The extra digit at the end
is the number of hops. If the router is on
the same subnet '1' is the number of hops.

Try this and see how it goes.

-Michael

[Tony Martin_1]

Hi Michael

Thanks for the heads up on the status of support I hope I'm not 'stretching the friendship' in terms of this forum by requesting help with his issue.

The local subnet does not have a dedicate router. Is a router a prerequisite for HP-UX to co-exists on a network. The HP-UX man pages actually alludes to the fact that the server itself can be the gateway - have I mis-understood something here?

I'm reasonably ignorant with respect to IP routing requirements but I believed that if packets were destined for the same subnet as the orginator (using the subnet mask as well - to identify logical subnets) that the packets were simply broadcast on that network.

I apologise if these issues are general network theory topics and not HP specific but I am struggling with trying to identify the source of my problems.

Regards
Tony

[Santosh Nair_1]

Something doesn't look right...the default route for the HP box should have the flags UG, i.e. U=up, G=gateway. Can you post the output of the following commands:

netstat -ni
netstat -nr
ifconfig lan0

-Santosh

[Darrell Allen]

Hi Tony,

Just some thoughts...

It shouldn't matter what the router is as long as it routes IP packets. And yes, UNIX servers can be configured as routers.

The default route should be identified as a gateway - do so by specifying a hop count as Michael suggests.

HPUX doesn't require a router on the network. A router is only needed if packets must be routed to a different subnet. Communication with the other boxes on the subnet can be done without a router.

I'd expect your routing table to have an entry for the local subnet. Something like:
10.0.0.0 10.0.0.X U 2 0 lan0 1500
where 10.0.0.X is the IP address of the HP.

I'd like to see the output from the 3 commands Santosh requested.

Verify the subnet mask is set on the HP (see output from above commands).

I don't have experience with HPUX 9.x (currently only have access to 11.0) but I have seen other UNIXes need a route to the local host via the loopback address like this:
10.0.0.3 127.0.0.1 UH 0 131541 lan0 4136

11.0 has a route to itself via itself (instead of the loopback) like this:
10.0.0.3 10.0.0.3 UH 0 131541 lan0 4136

Darrell

[Tony Martin_1]

Additional information as requested.

netstat -ni
??
Name?????????? Mtu?????????? Network?????? Address?????? 1pkts?????? 1errs?????? 0pkts?????? 0errs?????? Coll
lan0?????????????? 1497???????? 10??????????????10.0.0.10??????40???????????????? 29????????34025??????10399??????10401
ni0*???????????????? 0??????????????none??????????none????????????????0???????????????????? 0???????????? 0???????????? 0?????????????????? 0
ni1*???????????????? 0??????????????none??????????none????????????????0???????????????????? 0??????????????0???????????? 0????????????????????0
lo0?????????????????? 4608???????? 127??????????127.0.0.1???? 136???????????????? 0??????????????136??????????0????????????????????0
??
??
??
netstat -nr
??
Routing tables
Destination?????????????????????? Gateway?????????????? Flags?????????????? Refs?????????????? Use?????????????? Interface
127.0.0.1?????????????????????????????? 127.0.0.1???????????? UH?????????????????????? 0?????????????????????? 136?????????????? lo0
default????????????????????????????????????10.0.0.2???????????????? U?????????????????????? 0?????????????????????? 3846???????????? lan0
??
??
ifconfig lan0
??
lan0: flags=863
inet 10.0.0.10 netmask ffff0000 broadcast 10.0.255.255

[Darrell Allen]

Hi again,

First, change your netmask. The ifconfig shows it as ffff0000 (255.255.0.0). Use:
ifconfig lan0 10.0.0.10 netmask 255.255.255.0 up

Next, remove the current default route entry with:
route delete default 10.0.0.2

Then, as Michael suggested, set the default route like this:
route add default 10.0.0.2 1

See if that helps.

Also just noticed you have way too many oerrs and collisions for the number of packets you are transmitting. Verify you have a good network cable. If using twisted pair cabling and a switch, verify the HP and the switch have the same duplex setting. Full duplex on one side and half on the other will cause problems.

Darrell

[Wodisch]

Hello,

it seems to be a quite simple (and common) failure:
you omitted/forgot (?) the *metric* (sometimes called "hop-count") - it must be greater then zero, if the router is another station...
By omitting you got the default of 0, which means: the router is built-in into your HP-UX station (which it is not, of course).
When you have a route to another station it always must show the flag "G" (=gateway=router) in the flags column of "netstat -r" - it does not on your output...

HTH,
Wodisch

[Sanjay_6]

Hi Tony,

Try these links,

http://us-support3.external.hp.com/cki/bin/doc.pl/sid=bb6005951d27734b71/screen=ckiDisplayDocument?docId=200000024605297

http://us-support3.external.hp.com/cki/bin/doc.pl/sid=bb6005951d27734b71/screen=ckiDisplayDocument?docId=200000045145904

Hope this helps.

regds