need help in adding a computer to internal home network (host unreachable)

Hi,

I am trying to add another computer to my internal home network. My main
computer, say HomeR (running Debian Sarge 2.4.24-1-686), working as a
router has two NICs. It's eth0 connects to the high speed modem and eth1
connects to a switch and has the configuration:
#-------------------------------------------------------------------
#> cat /etc/network/interfaces
# Used by ifup(8) and ifdown(8). See the interfaces(5) manpage or
# /usr/share/doc/ifupdown/examples for more information.
# /etc/network/interfaces -- configuration file for ifup(8), ifdown(8)

# The loopback interface
auto lo
iface lo inet loopback

# The first network card - this entry was created during the Debian
installation
# (network, broadcast and gateway are optional)
auto eth0
iface eth0 inet static
address 192.168.1.0
netmask 255.255.255.0
network 192.168.0.0
broadcast 192.168.0.255
# gateway 192.168.10.1
pre-up /etc/iptables/iptables.sh panic
pre-up /etc/iptables/iptables.sh preup_start
auto eth1
iface eth1 inet static
address 192.168.0.2
netmask 255.255.255.0
network 192.168.0.0
broadcast 192.168.0.255
# gateway 192.168.1.0
#-------------------------------------------------------------------
The route command on HomeR gives:
#> route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
a.b.c.d 0.0.0.0 255.255.255.255 UH 0 0 0 ppp0
192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
0.0.0.0 a.b.c.d 0.0.0.0 UG 0 0 0 ppp0

where a.b.c.d is the IP that my ISP provides each time I connect to it.


My two internal computer are connected to the swith from their NICs.

One of my internal home computers, say Home1, is 192.168.0.10 and is
working fine (ping, internet, ssh, etc. towards HomeR and outside). The
other, say Home2, is the one I am trying to add. I put in Knoppix and
set Home2 up as 192.168.0.11, with netmask 255.255.255.0, gateway
192.168.0.2 and with the nameserves which are listed in
/etc/resolve.conf of HomeR (the router machine).

I cannot ping to or from 192.168.0.11 any other computer. Domain names
do not get resolved. If I try pinging it from HomeR, I get:
# ping -c4 192.168.0.11
PING 192.168.0.11 (192.168.0.11) 56(84) bytes of data.
From 192.168.0.2 icmp_seq=1 Destination Host Unreachable
From 192.168.0.2 icmp_seq=2 Destination Host Unreachable
From 192.168.0.2 icmp_seq=3 Destination Host Unreachable
From 192.168.0.2 icmp_seq=4 Destination Host Unreachable

--- 192.168.0.11 ping statistics ---
4 packets transmitted, 0 received, +4 errors, 100% packet loss, time 3000ms
, pipe 3


But if I disconnect Home1 from the internal LAN, and do 'tcpdump -i
eth1' on HomeR, and ping HomeR from Home2, I get:
# tcpdump -i eth1
tcpdump: listening on eth1
03:19:03.838878 arp who-has 192.168.0.2 tell 192.168.0.11
03:19:03.838928 arp reply 192.168.0.2 is-at 0:50:ba:50:3:87
03:19:04.833008 arp who-has 192.168.0.2 tell 192.168.0.11
03:19:04.833039 arp reply 192.168.0.2 is-at 0:50:ba:50:3:87
03:19:05.833046 arp who-has 192.168.0.2 tell 192.168.0.11
03:19:05.833091 arp reply 192.168.0.2 is-at 0:50:ba:50:3:87


But if I do 'tcpdump -i eth0' on Home2 and ping Home2 from HomeR, I get
no activity. So it seems that Home2 is able to send packets to the
192.168.0.0 network, but no other machine is able to send any to
192.168.0.11(Home2).


Any ideas what could be going wrong or how do I go about solving this?

Thanks a ton,
->HS


--
(Please remove all underscores from my email address to get the correct
one. Apologies for the inconvenience, but this is to reduce spam.)

or have I not described the problem properly? I am at wit's end, not
sure what is wrong with my network. Could use some help.

->HS



Apparently, _H. S._, on 04/29/04 03:35,typed:
> Hi,
>
> I am trying to add another computer to my internal home network. My main
> computer, say HomeR (running Debian Sarge 2.4.24-1-686), working as a
> router has two NICs. It's eth0 connects to the high speed modem and eth1
> connects to a switch and has the configuration:
> #-------------------------------------------------------------------
> #> cat /etc/network/interfaces
> # Used by ifup(8) and ifdown(8). See the interfaces(5) manpage or
> # /usr/share/doc/ifupdown/examples for more information.
> # /etc/network/interfaces -- configuration file for ifup(8), ifdown(8)
>
> # The loopback interface
> auto lo
> iface lo inet loopback
>
> # The first network card - this entry was created during the Debian
> installation
> # (network, broadcast and gateway are optional)
> auto eth0
> iface eth0 inet static
> address 192.168.1.0
> netmask 255.255.255.0
> network 192.168.0.0
> broadcast 192.168.0.255
> # gateway 192.168.10.1
> pre-up /etc/iptables/iptables.sh panic
> pre-up /etc/iptables/iptables.sh preup_start
> auto eth1
> iface eth1 inet static
> address 192.168.0.2
> netmask 255.255.255.0
> network 192.168.0.0
> broadcast 192.168.0.255
> # gateway 192.168.1.0
> #-------------------------------------------------------------------
> The route command on HomeR gives:
> #> route -n
> Kernel IP routing table
> Destination Gateway Genmask Flags Metric Ref Use Iface
> a.b.c.d 0.0.0.0 255.255.255.255 UH 0 0 0 ppp0
> 192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
> 192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
> 0.0.0.0 a.b.c.d 0.0.0.0 UG 0 0 0 ppp0
>
> where a.b.c.d is the IP that my ISP provides each time I connect to it.
>
>
> My two internal computer are connected to the swith from their NICs.
>
> One of my internal home computers, say Home1, is 192.168.0.10 and is
> working fine (ping, internet, ssh, etc. towards HomeR and outside). The
> other, say Home2, is the one I am trying to add. I put in Knoppix and
> set Home2 up as 192.168.0.11, with netmask 255.255.255.0, gateway
> 192.168.0.2 and with the nameserves which are listed in
> /etc/resolve.conf of HomeR (the router machine).
>
> I cannot ping to or from 192.168.0.11 any other computer. Domain names
> do not get resolved. If I try pinging it from HomeR, I get:
> # ping -c4 192.168.0.11
> PING 192.168.0.11 (192.168.0.11) 56(84) bytes of data.
> From 192.168.0.2 icmp_seq=1 Destination Host Unreachable
> From 192.168.0.2 icmp_seq=2 Destination Host Unreachable
> From 192.168.0.2 icmp_seq=3 Destination Host Unreachable
> From 192.168.0.2 icmp_seq=4 Destination Host Unreachable
>
> --- 192.168.0.11 ping statistics ---
> 4 packets transmitted, 0 received, +4 errors, 100% packet loss, time 3000ms
> , pipe 3
>
>
> But if I disconnect Home1 from the internal LAN, and do 'tcpdump -i
> eth1' on HomeR, and ping HomeR from Home2, I get:
> # tcpdump -i eth1
> tcpdump: listening on eth1
> 03:19:03.838878 arp who-has 192.168.0.2 tell 192.168.0.11
> 03:19:03.838928 arp reply 192.168.0.2 is-at 0:50:ba:50:3:87
> 03:19:04.833008 arp who-has 192.168.0.2 tell 192.168.0.11
> 03:19:04.833039 arp reply 192.168.0.2 is-at 0:50:ba:50:3:87
> 03:19:05.833046 arp who-has 192.168.0.2 tell 192.168.0.11
> 03:19:05.833091 arp reply 192.168.0.2 is-at 0:50:ba:50:3:87
>
>
> But if I do 'tcpdump -i eth0' on Home2 and ping Home2 from HomeR, I get
> no activity. So it seems that Home2 is able to send packets to the
> 192.168.0.0 network, but no other machine is able to send any to
> 192.168.0.11(Home2).
>
>
> Any ideas what could be going wrong or how do I go about solving this?
>
> Thanks a ton,
> ->HS
>
>


--
(Please remove all underscores from my email address to get the correct
one. Apologies for the inconvenience, but this is to reduce spam.)

On Thu, 29 Apr 2004 03:35:17 -0400, H. S. wrote:
> I am trying to add another computer to my internal home network. My main
> computer, say HomeR (running Debian Sarge 2.4.24-1-686), working as a
> router has two NICs. It's eth0 connects to the high speed modem and eth1

If you're using PPPoE, which it appears from other information you
posted, IIUC the eth0 interface should have no IP assigned.

> # Used by ifup(8) and ifdown(8). See the interfaces(5) manpage or
> # /usr/share/doc/ifupdown/examples for more information.
> # /etc/network/interfaces -- configuration file for ifup(8), ifdown(8)

Did you consult these man pages and examples? That's all Debian-
specific, and I cannot help with that. In fact the majority of your
post seems to be Debian-specific.

> The route command on HomeR gives:
> #> route -n
> Kernel IP routing table
> Destination Gateway Genmask Flags Metric Ref Use Iface
> a.b.c.d 0.0.0.0 255.255.255.255 UH 0 0 0 ppp0
> 192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
> 192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
> 0.0.0.0 a.b.c.d 0.0.0.0 UG 0 0 0 ppp0
>
> where a.b.c.d is the IP that my ISP provides each time I connect to it.

The gateway IP should be the pppd peer IP. /sbin/ifconfig output might
be more useful here.

> other, say Home2, is the one I am trying to add. I put in Knoppix and
> set Home2 up as 192.168.0.11, with netmask 255.255.255.0, gateway
> 192.168.0.2 and with the nameserves which are listed in
> /etc/resolve.conf of HomeR (the router machine).
>
> I cannot ping to or from 192.168.0.11 any other computer. Domain names

So that is the machine with the problem ... why are you posting the
information from the router? Try ifconfig on the troubled client, and
the "route -n" from there.

> Any ideas what could be going wrong or how do I go about solving this?

Guess: broken routing on home2?
--
/dev/rob0 - preferred_email=i$((28*28+28))@softhome.net
or put "not-spam" or "/dev/rob0" in Subject header to reply

Apparently, _/dev/rob0_, on 04/29/04 16:24,typed:

>>I cannot ping to or from 192.168.0.11 any other computer. Domain names
>
>
> So that is the machine with the problem ... why are you posting the
> information from the router? Try ifconfig on the troubled client, and
> the "route -n" from there.
>
>
>>Any ideas what could be going wrong or how do I go about solving this?
>
>
> Guess: broken routing on home2?

Okay, here is what Home2 gives me:

$> route -n
~# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
0.0.0.0 192.168.0.2 0.0.0.0 UG 0 0 0 eth0

$> ifconfig -a
eth0 Link encap:Ethernet HWaddr 00:0C:41:1D:32:3E
inet addr:192.168.0.11 Bcast:192.168.0.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:14 dropped:0 overruns:0 frame:16
TX packets:28 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:2376 (2.3 KiB)
Interrupt:11 Base address:0xd800

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:26 errors:0 dropped:0 overruns:0 frame:0
TX packets:26 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:2664 (2.6 KiB) TX bytes:2664 (2.6 KiB)


BTW, as I mentioned earlier, Home1 machine is running Win98 and is
working fine as far as the network is concerned. It's IP is
192.168.0.10. Now if I unplug Home1's LAN cable and connect it to
Home2's NIC and change Home2's IP as 192.168.0.10, thereby effectively
making Home2 as Home1 (from network's point of view), the new machine
still can't ping anything else, i.e. the problem remains the same.

Hopefully the above information will help to narrow down the problem.

thanks for your suggestions,
->HS

--
(Please remove all underscores from my email address to get the correct
one. Apologies for the inconvenience, but this is to reduce spam.)

On Thu, 29 Apr 2004 17:13:59 -0400, H. S. wrote:
>> Guess: broken routing on home2?
>
> Okay, here is what Home2 gives me:

Routing looks fine.

> $> ifconfig -a
> eth0 Link encap:Ethernet HWaddr 00:0C:41:1D:32:3E
> inet addr:192.168.0.11 Bcast:192.168.0.255 Mask:255.255.255.0
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:0 errors:14 dropped:0 overruns:0 frame:16
^^ ^^
But this does NOT. You've got either a physical problem with the NIC,
media (cables), or the Ethernet driver.

> BTW, as I mentioned earlier, Home1 machine is running Win98 and is
> working fine as far as the network is concerned. It's IP is
> 192.168.0.10. Now if I unplug Home1's LAN cable and connect it to
> Home2's NIC and change Home2's IP as 192.168.0.10, thereby effectively
> making Home2 as Home1 (from network's point of view), the new machine

No need to change the IP, but swapping the cable eliminates that as a
suspect. Bad NIC or driver problem.

> Hopefully the above information will help to narrow down the problem.

Usually when ifconfig shows errors, it means it. :) I did see one time
where a buggy tulip NIC showed errors yet it worked fine.
--
/dev/rob0 - preferred_email=i$((28*28+28))@softhome.net
or put "not-spam" or "/dev/rob0" in Subject header to reply

Apparently, _/dev/rob0_, on 04/29/04 21:40,typed:
> No need to change the IP, but swapping the cable eliminates that as a
> suspect. Bad NIC or driver problem.
>
>
>>Hopefully the above information will help to narrow down the problem.
>
>
> Usually when ifconfig shows errors, it means it. :) I did see one time
> where a buggy tulip NIC showed errors yet it worked fine.


I did consider that possibility. So I changed the NIC and used a brand
new LinkSys NIC. Same symptons. Though I need to verify that the driver
the knoppix was using was not reported to have shown any problem, and
also I am yet to test the new NIC in WinXP (it is going to be a dual
boot machine). Quite honestly, this is driving me nuts ... grrr.

BTW, last night, I started pinging HomeR (router machine) from Home2
(the problem machine),and started "tcpdump -i eth1" on HomeR. It showed
some activity (no other machine was connected to the switch, so Home2
was the only machine on my internal LAN). So I inferred from that the
NIC on Home2 was able to send data to the LAN but was not able to
receive it or understand it. I am not sure what this leads to, but it is
another sympton.

->HS



--
(Please remove all underscores from my email address to get the correct
one. Apologies for the inconvenience, but this is to reduce spam.)

Apparently, _/dev/rob0_, on 04/29/04 21:40,typed:
> On Thu, 29 Apr 2004 17:13:59 -0400, H. S. wrote:
>
>>>Guess: broken routing on home2?
>>
>>Okay, here is what Home2 gives me:
>
>
> Routing looks fine.
>
>
>>$> ifconfig -a
>>eth0 Link encap:Ethernet HWaddr 00:0C:41:1D:32:3E
>> inet addr:192.168.0.11 Bcast:192.168.0.255 Mask:255.255.255.0
>> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
>> RX packets:0 errors:14 dropped:0 overruns:0 frame:16
>
> ^^ ^^
> But this does NOT. You've got either a physical problem with the NIC,
> media (cables), or the Ethernet driver.
>
>
>>BTW, as I mentioned earlier, Home1 machine is running Win98 and is
>>working fine as far as the network is concerned. It's IP is
>>192.168.0.10. Now if I unplug Home1's LAN cable and connect it to
>>Home2's NIC and change Home2's IP as 192.168.0.10, thereby effectively
>>making Home2 as Home1 (from network's point of view), the new machine
>
>
> No need to change the IP, but swapping the cable eliminates that as a
> suspect. Bad NIC or driver problem.
>
>
>>Hopefully the above information will help to narrow down the problem.
>
>
> Usually when ifconfig shows errors, it means it. :) I did see one time
> where a buggy tulip NIC showed errors yet it worked fine.


It was the cable!

So: HomeR is connected to the switch (a 1->4 switch). Home1 and Home2
were connected to the switch. The problem computer was Home2. While
debugging the problem, I replaced the cable of Home1 with the one that I
was using for Home2, and Home1 worked perfectly, thus eliminating the
cable as the problem. But while trying an older cable with Home2, we
observed Home2 then worked okay!! So it was the cable, which
coincidently worked okay with Home1 but not with Home2. Now that we have
replaced the cable, all inter LAN is working okay.

--
(Please remove all underscores from my email address to get the correct
one. Apologies for the inconvenience, but this is to reduce spam.)