I have set a network of two debian machines using a switch

sun (192.168.0.1) and sun1(192.168.0.2)

I can't ping from both machines

sun1 is a pI machine

while running tcp dump on sun, and running ping 192.168.0.1 from .2 gives

18:31:08.170698 arp who-has sun tell 192.168.0.2
18:31:08.170708 arp reply sun is-at 00:18:f3:da:a2:09 (oui Unknown)

and ping 192.168.0.2 from 192.168.0.1 gives

19:11:27.735757 arp who-has 192.168.0.2 tell sun
19:11:28.735768 arp who-has 192.168.0.2 tell sun

what is the problem?

What is a "pl machine"?

Let's see the subnet mask you're using for each of those boxes. Also, would it be possible to use IPs 192.168.0.2 and 192.168.0.3 instead? (e.g. It's common for .1 of a /24 subnet to be a default router...)

Oh I mean Pentium I machine 128MB RaM CD drive not functioning to install other programs

Subnet mask 255.255.255.0

sun:/home/sunil# ifconfig
eth0 Link encap:Ethernet HWaddr 00:18:F3A:A2:09
inet addr:192.168.0.2 Bcast:192.168.0.255 Mask:255.255.255.0
inet6 addr: fe80::218:f3ff:feda:a209/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:62 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:8122 (7.9 KiB)
Interrupt:233 Base address:0xa400

eth1 Link encap:Ethernet HWaddr 00:80:48:51:2C:A3
inet addr:116.68.83.141 Bcast:255.255.255.255 Mask:255.255.240.0
UP BROADCAST RUNNING MULTICAST MTU:576 Metric:1
RX packets:63663 errors:0 dropped:0 overruns:0 frame:0
TX packets:2291 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:5202695 (4.9 MiB) TX bytes:268420 (262.1 KiB)
Interrupt:50 Base address:0xe800

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:67 errors:0 dropped:0 overruns:0 frame:0
TX packets:67 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:5109 (4.9 KiB) TX bytes:5109 (4.9 KiB)

/etc/host/interfaces contents
------------------------------

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
allow-hotplug eth1
auto eth1
iface eth1 inet dhcp
auto eth0
iface eth0 inet static
address 192.168.0.2
netmask 255.255.255.0
network 192.168.0.0
route add -net 192.168.0.0 netmask 255.255.255.0 dev eth0

For the second machine (Pentium I)
TX packets:0 errors:10 dropped:0 overruns:0 carrier:0

So, this is a multi-homed server. My guess is you're having routing issues. How about posting ifconfig output from the other box as well, and also netstat -rn output from both?

for 192.168.0.2
sun:/home/sunil# netstat -rn
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
116.68.80.0 0.0.0.0 255.255.240.0 U 0 0 0 eth1
0.0.0.0 116.68.80.1 0.0.0.0 UG 0 0 0 eth1

for 192.168.0.3
sunil:~# netstat -rn
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0

ifconfig output

sunil:~# ifconfig


eth0 Link encap:Ethernet HWaddr 52:54:AB:15:71:24
inet addr:192.168.0.3 Bcast:192.168.0.255 Mask:255.255.255.0
inet6 addr: fe80::5854:abff:fe15:7124/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:3 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:468 (468.0 b)
Interrupt:11 Base address:0xd800
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:24 errors:0 dropped:0 overruns:0 frame:0
TX packets:24 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:1584 (1.5 KiB) TX bytes:1584 (1.5 KiB)

I see you've changed the host IPs to use .2 and .3 instead. Assuming that alone did not solve the issue, which is sun and which is sun1 now?

This would be easier to follow if you could post more complete command-line sessions, e.g.:

"While pinging from sun to sun1, I see the following:"
(Which brings up another point -- be sure you're sniffing the correct interface.)

I have changed the IP numbers 192.168.0.1->192.168.0.2 (sun)-eth0
192.168.0.2->192.168.0.3 (sun1)

I have issued the tcpdump command from the machine sun (192.168.0.2 - having 2 interfaces)
It is a AMD sempron machine.


The other one 192.168.0.3 (sun1) is a PI machine. I can't install packages on that machine now because the CD ROM is not working now (so I can't run tcpdump from this machine)

I have issued the ifconfig command on sun1 and mannually entered the information to this post

========================

tcpdump -i eth0(192.168.0.2) on sun

18:52:00.256332 arp who-has sun tell 192.168.0.3
18:52:03.255879 arp who-has sun tell 192.168.0.3
18:52:06.255437 arp who-has sun tell 192.168.0.3
18:52:08.255110 arp who-has sun tell 192.168.0.3

tcpdump -i eth1(dhcp) on sun

18:51:34.144862 arp who-has 116.68.74.135 tell 116.68.72.1
18:51:34.152679 arp who-has 116.68.64.109 tell 116.68.64.1
18:51:34.162547 arp who-has 116.68.65.47 tell 116.68.64.1
18:51:34.184073 arp who-has 116.68.73.107 tell 116.68.72.1
18:51:34.193356 arp who-has 116.68.71.83 tell 116.68.64.1

213 packets captured
2038 packets received by filter
1469 packets dropped by kernel

I must be missing something. Layer 2 traffic (arp query) is reaching eth0 on sun, but layer 3 traffic (icmp echo request) is not. It seems like sun doesn't believe he is on the same subnet as sun1. What sort of switch are you using for the 192.168.0/24 network?

Yes that is the problem. The machine sun receives packets from machine sun1 while pinging from sun1. The machine send arp replies also (See my first posting). Is the replied packets not reachine the machine sun1? Or the sun1 machine is unable to capture the packets?

Do you have a crossover cable by any chance? To eliminate the switch itself as a possible cause, I'd connect the two 192.168.0/24 interfaces with a crossover cable and try again.

I have changed the switch and connected the two computers using a crossorver cable

But the same problem

From sun (at the same time ping 192.168.0.2 from sun1)
sun:/home/sunil# tcpdump -i eth0
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes
19:52:31.903404 arp who-has 192.168.0.2 tell 192.168.0.3
19:52:31.929675 arp reply 192.168.0.2 is-at 00:18:f3:da:a2:09 (oui Unknown)
19:52:33.903073 arp who-has 192.168.0.2 tell 192.168.0.3
19:52:33.903084 arp reply 192.168.0.2 is-at 00:18:f3:da:a2:09 (oui Unknown)
19:52:36.902625 arp who-has 192.168.0.2 tell 192.168.0.3
19:52:36.902641 arp reply 192.168.0.2 is-at 00:18:f3:da:a2:09 (oui Unknown)
19:52:39.902180 arp who-has 192.168.0.2 tell 192.168.0.3
19:52:39.902196 arp reply 192.168.0.2 is-at 00:18:f3:da:a2:09 (oui Unknown)
19:52:41.901886 arp who-has 192.168.0.2 tell 192.168.0.3

I think the error is with the network card of sun1
mii-tool from sun1 gives

SIOCGMIIPHY on 'eth0' failed:Operation not supported
no MII interfaces found

But then if that is the case how the packet from sun1 reached in sun?