Major Ping Problems

[Richard Schiavi]

We have a HP 9000 server running Unix 11.00 when we ping this server we are receiving 255 packets received for every packet sent. We are using a 255.255.0.0 subnet mask. Any ideas as to why this is happening. We are unable to get NFS automount to work because of this.

[harry d brown jr]

What IP address are you ping'ing???

Do you possibly have duplicate IP's out there?

live free or die
harry

[Richard Schiavi]

From another server we are pinging 10.56.30.73
I don't think there are duplicate IP'S out there, But I am not sure. We are using MC-Service Guard and do have a cluster installed. We have 2 identical servers HA1 and HA2. If we ping HA1 from HA2 it is normal
If we ping from HA1 to HA2 notice the problem.

[harry d brown jr]

ah, the ole "cluster of a problem". I'm not too familiar with mcsg, but until someone else pipes in try the following:

How about a traceroute ?

http://hpux.cs.utah.edu/hppd/hpux/Networking/Admin/traceroute-991603/


live free or die
harry

[Joaquin Gil de Vergara]

please send me the output of command

netstat -in

in thw two servers

thanks

[Bill Thorsteinson]

It looks like you are pinging
a subnet. If you ping an
address ending in 255 and you
have computers setup up with
a class C mask 255.255.255.0
they will respond to the ping.

This can be used for Denial of
Service attacks. Some system
allow you to disable responding to pings on the
broadcast address.

[Richard Schiavi]

I have attached the file with the information

[Joaquin Gil de Vergara]

it looks well

please run

ifconfig lan0
ifconfig lan1
ifconfig lan1:1

in both systems

thanks

[Richard Schiavi]

I have attached the ifconfig file. It looks correct.

[Joaquin Gil de Vergara]

Yes, it's correct

perhaps there is any error in local arp cache

please run

arp -a

after the ping

Thanks

[Anthony deRito]

Are both server pointing tho the same default gateways? Is is possible you have a routing loop involved with multiple gateways?

[Ron Kinner]

What does your LAN look like? Do you have multiple hubs or switches running spanning tree? Could be a loop in the LAN.

Is there a router anywhere? If the router pings each box do you get the same response. IF the router is unplugged from the LAN does the response change?

Ron

[harry d brown jr]

Richard,

Can you install and run the trace route?

live free or die
harry

[Ron Kinner]

Howabout running netstat -n again, on both boxes before and directly after a ping. Do you see the expected number of incoming packets (one for each ping) on the target box? Does it really send out 255 times as many reply packets as it gets ping packets? Does the sender really only send out one packet or does it send out 255 for each ping? Is it really receiving 255 packets for each ping it sends out?

Ron

[rick jones]

255 replies certianly sounds like some sort of routing loop - the default TTL in HP-UX 11 is 255 (the max).

as an experiment (perhaps unneeded with traceroute results already finding a busted router) you could alter the TTL - first on the side doing the ping, then on the side responding to the ping.

ndd -h | grep ttl - probably the ones involving "ip" rather than UDP or TCP...

You might also just check the arp caches on either side to make sure that for some strange reason a broadcast/multicast MAC address was not cached as the IP to MAC mapping.