Ping Linux > XP

david63 · 05-14-2003, 03:23 AM

I have the following setup:

XP machine on IP 192.168.0.4
ICS (on XP) on IP 192.168.0.1
Router on IP 192.168.0.101
Linux machine on IP 192.168.0.3
Linux Gateway on IP 192.168.0.1

Everything works - XP can see Linux, Linuc can see XP, Linux can access Internet via XP, Linux can print via XP.

The strange thing is that if I try to ping 192.168.0.4 from the Linux I get a Destination Host Unreachable message yet I have no problem pinging 192.168.0.1 from the Linux.

Can anyone explain this as I am a little confused?

jharris · 05-14-2003, 03:43 AM

Is "linux gateway" supposed to have the same IP as "ICS (on XP)?? Whats the output from ifconfig and route -n on your linux box?

cheers

Jamie...

david63 · 05-14-2003, 06:30 AM

Yes - the Linux gateway needs the same address as ICS as it is being "passed through" the XP machine.

jharris · 05-14-2003, 07:04 AM

Can you explain a little further, I've never known a setup were you can have non-unique IP addresses unless you are manipulating ARP on the lan to control which machine gets the packets. How about the requested output from ifconfig and route -n?

cheers

Jamie...

david63 · 05-14-2003, 07:37 AM

This is what I was advised to do AND IT WORKS. Perhaps there is another way - if so please let me know and I will try it!

ifconfig

Code:

eth0      Link encap:Ethernet  HWaddr 00:30:BD:1F:AE:0E
          inet addr:192.168.0.3  Bcast:192.168.0.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:4637343 errors:0 dropped:0 overruns:0 frame:0
          TX packets:3202308 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:100
          RX bytes:2328130018 (2220.2 Mb)  TX bytes:292761906 (279.1 Mb)
          Interrupt:5 Base address:0x3000

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:897 errors:0 dropped:0 overruns:0 frame:0
          TX packets:897 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:112625 (109.9 Kb)  TX bytes:112625 (109.9 Kb)

route -n:

Code:

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
127.0.0.0       0.0.0.0         255.0.0.0       U     0      0        0 lo
0.0.0.0         192.168.0.1     0.0.0.0         UG    0      0        0 eth0

jharris · 05-14-2003, 08:08 AM

Quote:

Originally posted by david63
AND IT WORKS.

If clearly doesn't as you're having these problems! What exactly are you trying to accomplish? And what is the "ICS" bit on the XP box? As you have two machines with the same address you can't be sure which device would answer your ping even if it got there. The message of "Destination Host Unreachable" normally indicates that you don't have a route to that host for some reason. When you say

Quote:

The strange thing is that if I try to ping 192.168.0.4 from the Linux I get a Destination Host Unreachable message yet I have no problem pinging 192.168.0.3 from the Linux.

Do you mean you are on machine 192.168.0.1 (linux machine as you called it) or are you on 192.168.0.3 (linux gateway).

From the box in question what does traceroute 192.168.0.1 tell you?

cheers

Jamie...

david63 · 05-14-2003, 05:02 PM

Sorry I have been so long replying - had to go to an AGM!

ICS on the XP is Internet Connection Sharing

The output from traceroute is:

Code:

traceroute to 192.168.0.1 (192.168.0.1), 30 hops max, 38 byte packets
 1  * * *
 2  * * *
 3  * * *
 4  * * *
 5  * * *
 6  * * *
 7  * * *
 8  * * *
 9  * * *
10  * * *
11  * * *
12  * * *
13  * * *
14  * * *
15  * * *
16  * * *
17  * * *
18  * * *
19  * * *
20  * * *
21  * * *
22  * * *
23  * * *
24  * * *
25  * * *
26  * * *
27  * * *
28  * * *
29  * * *
30  * * *

When I am on the Linux (192.168.0.3) I cannot ping the XP (192.168.0.4) but I can ping the Linux (192.168.0.3) from the XP (192.168.0.4) - if that makes sense.

As I say everything works as I would expect - I am just curious as to why pinging the XP from Linux does not work but the Linux is clearly talking to the XP.

david_ross · 05-14-2003, 05:06 PM

Do you mean that you have one linux box and one xp box and that the gateway ON the linux box is set to 192.168.0.1?

david63 · 05-14-2003, 05:09 PM

Yes as is ICS on the XP (this a default that cannot be changed)

XavierP · 05-14-2003, 05:10 PM

On your XP box, is the built in firewall set to block the Linux box? or pings from outside?

david63 · 05-14-2003, 05:14 PM

I do not use the built in firewall - I have another one. I have disabled it and I still cannot ping the XP

XavierP · 05-14-2003, 05:22 PM

I wonder if it's because both gateways have the same address..... could you run ipconfig /all on your XP box - we'll be able to compare the 2 outputs. In the meantime, could you assign one of your gateways a new, unique address and let us know if that helps.