topic Re: Red Hat ES with isolated network and hub. in Operating System - Linux

Red Hat ES with isolated network and hub.

Ratzie — Wed, 16 Jun 2004 16:06:33 GMT

I have a problem that I know is at the tip of my tounge and cant spit it out.

I needed to set up a Red Hat server 192.168.2.1/255.255.255.0 on an isolated network. 192.168.2.0

I will have 10 pc's connected to it thru a hub.
Back to networking 101...

I have the crossover switch on for the port on the server to the hub. Light is on.

I then hooked up the test pc and gave it an address of 192.168.2.11/255.255.255.0

I am assuming that I dont need a default gateway, because it is on the same subnet. And no traffic should be going out anyway.

The files that I changed were...
[root@backgate sysconfig]$ more network
NETWORKING=yes
HOSTNAME=backgate

[root@backgate network-scripts]# more ifcfg-eth0
DEVICE=eth0
BOOTPROTO=static
BROADCAST=192.168.2.255
IPADDR=192.168.2.1
NETMASK=255.255.255.0
NETWORK=192.168.2.0
ONBOOT=yes

The /etc/hosts file remained the same since the only entry was ...
[root@lnxgate etc]# more hosts
# Do not remove the following line, or various programs
# that require network functionality will fail.
127.0.0.1 localhost.localdomain localhost

Did a restarted the server and when I try to ping 192.168.2.11
I get
Destination Host Unreachable

What am I missing?

Re: Red Hat ES with isolated network and hub.

Steven E. Protter — Wed, 16 Jun 2004 16:39:43 GMT

Try a regular straight through cable.

I don't think a crossover cable is required unless you are going nic to nic without a hub.

bub

Give that a shot and report back.

SEP

Re: Red Hat ES with isolated network and hub.

Stuart Browne — Wed, 16 Jun 2004 17:58:42 GMT

Another thing to check when the machine is up is the output of the following commands:

mii-tool eth0
netstat -nr

'mii-tool' should report whether it thinks there's a link or not. The 'netstat -nr' is to show the routing table, to ensure that the correct subnet gets bound to the interface.

Looking at the config you've shown us, it should be (unless you changed these files and didn't either restart networking or the entire machine at least).

Re: Red Hat ES with isolated network and hub.

Martin P.J. Zinser — Wed, 16 Jun 2004 21:08:39 GMT

Hi,

for starters, avoid the cross over port on the hub, this is meant for cascading hubs etc.

Connect your server with a regular cable to a
normal port on the hub. Try again ;-)

Also I do have my routes for a similar config setup like this

10.0.0.0 0.0.0.0 255.0.0.0 eth0
default 10.0.0.253 - -

Only difference is that 10.0.0.253 is my router to the internet. Note the route for my local network.

Greetings, Martin

Re: Red Hat ES with isolated network and hub.

Ratzie — Thu, 17 Jun 2004 07:25:18 GMT

I am going to chalk this up to bad karma. Or a bad connection with the PC cable.

Took it all apart brought it back into the lab, and low and behold it works, with and with out the cross over. With and with out a gateway.

Thanks for all the help.

I would like clarifications between the different ping replys,
destination unreachable, and ping timed out...

Re: Red Hat ES with isolated network and hub.

R. Allan Hicks — Thu, 17 Jun 2004 13:08:57 GMT

In answer to your last question.....

Typically, network unreachable means that the machine is clueless on how to get to the remote machine. Generally happens with routing issues. However, since you are on the same network, I'm clueless on the why it would say that. The only feeble explanation that I can muster is perhaps you changed the file(s) and didn't restart the network services. Often, network changes do not take effect until one restarts xinetd or re-boots the machine. This could explain why you took everything apart and put it back together and it worked.

ping timed out means that the machine "thinks" it knows how to get to the remote destination, but the remote did not reply.