Network problem

sunils1973 · 11-18-2008, 09:11 AM

I have a AMD sempron machine and a PI 233 MHz machine

The AMD machine has to ethernet cards and having internet connection on one of the cards.

I would like to build up a network of these two computers with an 8 port switch. As it is a PI machine windows or other distros of linux are dead slow and takes hours of time for installation. I installed debian etch and is working satisfactorily though it is slow.

Windows XP is installed in the AMD machine and debian on PI

I have assigned 192.168.0.3 to the PI machine and able to ping this machine from that machine but doing so from the AMD machine creates a network unreachable message.
I have edited the networks interface correctly on the debian system
When I am trying to ping from one machine to other, the 2 led signals of the switches blinks - means something is happening in the switch when i issue the command. I have also added the proper route commands
route add -net 192.168.0.0 dev eth0

Can anyone help

dkm999 · 11-19-2008, 11:16 PM

It might be that your Debian machine is configured to ignore ICMP Echo requests; if that is so, the AMD box will decide the host is unreachable after a bit. To check this, try the command

Code:

# echo /proc/sys/net/ipv4/icmp_echo_ignore_all

This ought to print 0; if it prints 1, you should set it to 0 with

Code:

# echo 0>/proc/sys/net/ipv4/icmp_echo_ignore_all

But if your Windoze machine reports "Network Unreachable", that probably means that its route table is wrong, or the IP address of the ethernet interface that you have connected to the switch is not what you think it is.

If these simple checks do not yield anything, I commend you to the tcpdump manpage. Set this program to listen on the 192.168.0.3 interface of the Debian machine, and see what packets go in both directions.

sunils1973 · 11-20-2008, 08:42 AM

Quote:

Originally Posted by dkm999

It might be that your Debian machine is configured to ignore ICMP Echo requests; if that is so, the AMD box will decide the host is unreachable after a bit. To check this, try the command

Code:

# echo /proc/sys/net/ipv4/icmp_echo_ignore_all

This ought to print 0; if it prints 1, you should set it to 0 with

Code:

# echo 0>/proc/sys/net/ipv4/icmp_echo_ignore_all

But if your Windoze machine reports "Network Unreachable", that probably means that its route table is wrong, or the IP address of the ethernet interface that you have connected to the switch is not what you think it is.

If these simple checks do not yield anything, I commend you to the tcpdump manpage. Set this program to listen on the 192.168.0.3 interface of the Debian machine, and see what packets go in both directions.

I think tcpdump program is not installed in my debian computer. It reports with a file not found message.

Any other method?

dkm999 · 11-20-2008, 10:41 AM

You don't say what the results of the preliminary checks were, so I assume that you have actually followed up on them, and found that everything is OK there.

In that case, your best option is to install tcpdump and use it. I think on Debian machines, the command is apt-get. On my Fedora systems, tcpdump is not necessarily available to casual users; it is found in /usr/sbin. So you might want to check if your $PATH variable is set to include /sbin and /usr/sbin (or, if tcpdump is in one of these obscure directories, you can just invoke it explicitly. For example,

Code:

 # /sbin/tcpdump

sunils1973 · 11-21-2008, 11:09 AM

The first command simply echoed the /proc/sys/net/ipv4/icmp_echo_ignore_all

so I gave the second command

dkm999 · 11-21-2008, 11:18 AM

Oops! I must have been typing late at night. The correct command to examine the content of this value is

Code:

# cat /proc/sys/net/ipv4/icmp_echo_ignore_all