Linux machines can't see each other on LAN
 

Hello,

I have a simple three node home network with a router, a laptop, and a PC. The PC acts as a simple server and has Samba installed on it. It runs FC1-2.4.22-1.255.nptl.

The laptop is a dual boot computer with both WinXP and FC1 (same kernel as above) installed.

When the laptop is running WinXP, it can access the Samba server on the PC, ssh to it, and ping it. However, when the laptop is running FC1, it can't see the PC, and the PC can't see it. The laptop can access the gateway/router (IP Address 192.168.2.1), and access the web, it just seems to have a problem accessing anything on the LAN.

The issue doesn't seem to have anything to do with /etc/hosts, as I can't even ping the IP address, much less the associated alias, and the pings work for between PC and WinXP side of the laptop.

I've done a self-ping on the laptop (IP Address 192.168.2.4) to ensure that the static IP is correct. The PC (IP Address 192.168.2.2) works as well. It may also be worth mentioning that the laptop has both an ethernet card (eth0, which is disabled), and a wireless card (eth1, which is active).

I've pasted in my ifconfig and route info below for the laptop and verified that the inet addr and Mask are correct for the PC as well. The route info looks the same for the PC, except that the interface reads eth0 instead of eth1. Any suggestions as to what I may be doing wrong or may be missing?

Thanks.

Todd

eth1 Link encap:Ethernet HWaddr 00:02:2D:68:77:4B
inet addr:192.168.2.4 Bcast:192.168.2.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1009 errors:0 dropped:0 overruns:0 frame:0
TX packets:1126 errors:4 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:650095 (634.8 Kb) TX bytes:250907 (245.0 Kb)
Interrupt:10 Base address:0x100

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:3591 errors:0 dropped:0 overruns:0 frame:0
TX packets:3591 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:1603898 (1.5 Mb) TX bytes:1603898 (1.5 Mb)

Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.2.0 * 255.255.255.0 U 0 0 0 eth1
169.254.0.0 * 255.255.0.0 U 0 0 0 eth1
127.0.0.0 * 255.0.0.0 U 0 0 0 lo
default 192.168.2.1 0.0.0.0 UG 0 0 0 eth1

Maby a firewall Issue on the Linux laptop ??

I've disabled the firewalls on both systems and still get a 'Destination Unreachable' from the ping when I try to ping from PC to laptop or laptop to PC. Any other possible suggestions?

Thanks.

Todd

Run

#tcpdump

on both the systems and check how the traffic moves.

Hope both the systems are on the same subnet, hosts.allow, hosts.deny do not have any entries that may restrict traffic.

What does route -nv and arp -a tell you?

On route -nv I get the following on my PC:

Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.2.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth0
127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo
0.0.0.0 192.168.2.1 0.0.0.0 UG 0 0 0 eth0

On arp -a I get the following on my PC:

? (192.168.2.1) at 00:04:E2:19:4C:54 [ether] on eth0

The values are pretty much the same for the laptop, except eth0 is eth1 for the wireless card, it has a different MAC address, and the 192.168.2.0 line is listed twice with duplicate information under every header.

Both systems are on the same subnet, and I don't have anything configured for hosts.allow or hosts.deny at the moment.

Thanks.

Todd