routing problem

[Sprint Unix Team]

I can ping individual IP address from a machine. But when I try to ping the whole network, it returns response only from a particular machine. Also, I cant talk to some machines on the same lan. The netconf file and routing tables are all identical. Can somebody help???

[Vincenzo Restuccia]

firewall rules?

[Sprint Unix Team]

Nopes these lans are on the inside of the firewalls. So I dont think firewall is a issue here.

[Patrick Wallek]

Are you using the correct broadcast address to ping the whole network? Is there a machine, router, etc. that inadvertantly has the address?

Can you give an example of the output you are getting?

[Sprint Unix Team]

Patrick,

This is the output i get;
carbon.sci-isg.com#ping 10.12.107.0
PING 10.12.107.0: 64 byte packets
64 bytes from 10.12.107.168: icmp_seq=0. time=2. ms
64 bytes from 10.12.107.168: icmp_seq=1. time=0. ms
64 bytes from 10.12.107.168: icmp_seq=2. time=0. ms

[Richard Darling]

your ping response indicates that there is only one machine logged into the network? what machine is the 168 address? yours?

[Sprint Unix Team]

Richard,

Thats the issue I have. I get response only from one machine which is on the network. Its not my machine. Also there are other machines on the network when I ping them individually i get a response but not when I ping the network.

[Patrick Wallek]

I think you are using the wrong address as your broadcast address to ping the whole network. Do an 'ifconfig lan?' on your NIC and see what the broadcast address is set to.

Here's a sample from my machine:

# ifconfig lan1
lan1: flags=863
inet 172.30.1.88 netmask ffff0000 broadcast 172.30.255.255

My broadcast is 172.30.255.255 and if I ping to that address then I get a response from the whole network (at least I think, I haven't counted. I do get a response from more thing one machine though.).

I just tried 'ping 172.30.0.0' as well and it worked too. Now I'm confused........

[MANOJ SRIVASTAVA]

Check this out , in case you are having doubts that whetehr there are two machine susing the same ip then disconnect the one you know then try pinging it , incase you get a response then there two machine using the saem IP address .
Also it looks the default router is not setup correctly in case you have problems acroos the network.

Manoj

[Celso Medina Kern]

Hi,

It seems to be due to different subnetmasks among these systems. If not, it is a really weird behaviour. I would like to see output of these commands:
netstat -in
netstat -rn
lanscan
arp -a
ifconfig lan? # < 1 command for each lan;
And your network map.

[Juan González]

Hi,
there is a parameter for the network device /dev/ip that indicates when to repond to echo broadcast.
If you have HPUX 11.x (or Solaris) you can get this parameter using
#ndd /dev/ip ip_respond_to_echo_broadcast

and set it to 1 (true), if you needed, using
#ndd /dev/ip ip_respond_to_echo_broadcast 1

if you have HPUX 10.20 you must do
#nettune icmp_mask_agent

and to set it
#nettune -s icmp_mask_agent 1

Best regards