Ping Problems On Two-Machine Linux Network

Hi.

I wonder whether anyone out there can help me. I'm new to networking,
and have
set up my first simple network by connecting two P100 linux boxes with
an RJ-45
crossover cable. The first of these machines, 'methuselah', is
installed with a
D-Link DE-220PCT jumperless NE2000-type card, and is running Slackware
9. The
second, 'blockhead', is installed with an unidentified ISA
RTL8019-based
jumpered card, and is running Redhat 6.1. Both machines' LEDs come on
when I plug in the crossover cable, and flickering on one end causes
flickering at the
other, but I can't ping properly between them. There seems to be a
problem with
blockhead - the RTL8019-based card seems unable to receive (and also
seems to
transmit in periodic bursts).

I've disabled PnP in the BIOS on both machines, and have set the
appropriate
IRQ channels to Legacy ISA. I've also set the IO & IRQ jumpers on the
RTL8019
card to the correct settings, using a document (8019AS.pdf) I found on
the
RealTek website, but I didn't know what settings to use for the BROM
jumpers,
so I've left them unjumpered.

Anyway, I include below the data from both machines (first before
pinging, and
then during pinging, both from blockhead to methuselah, and from
methuselah to
blockhead). If there's any further information I could provide that
would be
useful, please ask!

I'd be very grateful for any help, as I've run out of ideas!
Thanks,

Paul.

************************************************** ****************************

Data for methuselah (192.168.0.1)
*********************************

Relevant section (last few lines) of dmesg:
*******************************************
ne.c:v1.10 9/23/94 Donald Becker ((E-Mail Removed))
Last modified Nov 1, 2000 by Paul Gortmaker
NE*000 ethercard probe at 0x340: 00 40 05 2c 7d 3d
eth0: NE2000 found at 0x340, using IRQ 10.

Output of ifconfig:
*******************
eth0 Link encap:Ethernet HWaddr 00:40:05:2C:7D:3D
inet addr:192.168.0.1 Bcast:192.168.0.255
Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
Interrupt:10 Base address:0x340

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:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)

Output of netstat -r:
*********************
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window
irtt Iface
localnet * 255.255.255.0 U 0 0
0 eth0
loopback * 255.0.0.0 U 0 0
0 lo

Output of netstat -i:
*********************
Kernel Interface table
Iface MTU Met RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP
TX-OVR Flg
eth0 1500 0 0 0 0 0 0 0 0
0 BMRU
lo 16436 0 0 0 0 0 0 0 0
0 LRU

Output of tcpdump -i eth0 (whilst being pinged by blockhead):
************************************************** ***********
tcpdump: listening on eth0
18:20:50.374116 arp who-has methuselah.junkyard tell
blockhead.junkyard
18:20:50.374230 arp reply methuselah.junkyard is-at 0:40:5:2c:7d:3d
18:21:00.372555 arp who-has methuselah.junkyard tell
blockhead.junkyard
18:21:00.372658 arp reply methuselah.junkyard is-at 0:40:5:2c:7d:3d
18:21:10.370985 arp who-has methuselah.junkyard tell
blockhead.junkyard
18:21:10.371113 arp reply methuselah.junkyard is-at 0:40:5:2c:7d:3d
18:21:20.369423 arp who-has methuselah.junkyard tell
blockhead.junkyard
18:21:20.369532 arp reply methuselah.junkyard is-at 0:40:5:2c:7d:3d

10 packets received by filter
0 packets dropped by kernel

Output of ping 192.168.0.2:
***************************
PING 192.168.0.2 (192.168.0.2) 56(84) bytes of data.
From 192.168.0.1 icmp_seq=1 Destination Host Unreachable
(repeated another 23 times before being stopped with <Ctrl>-C)

--- 192.168.0.2 ping statistics ---
26 packets transmitted, 0 received, +24 errors, 100% packet loss,
time 25136ms, pipe 3

************************************************** ****************************

Data for blockhead (192.168.0.2)
********************************

Relevant section (last few lines) of dmesg:
*******************************************
ne.c:v1.10 9/23/94 Donald Becker ((E-Mail Removed))
NE*000 ethercard probe at 0x340: 00 00 21 b1 82 08
eth0: NE2000 found at 0x340, using IRQ 10.

Output of ifconfig:
*******************
eth0 Link encap:Ethernet HWaddr 00:00:21:B1:82:08
inet addr:192.168.0.2 Bcast:192.168.0.255
Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
Interrupt:10 Base address:0x340

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:3924 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0

Output of netstat -r:
*********************
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window
irtt Iface
192.168.0.2 * 255.255.255.255 UH 0 0
0 eth0
192.168.0.0 * 255.255.255.0 U 0 0
0 eth0
127.0.0.0 * 255.0.0.0 U 0 0
0 lo

Output of netstat -i:
*********************
Kernel Interface table
Iface MTU Met RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP
TX-OVR Flg
eth0 1500 0 0 0 0 0 0 0 0
0 BRU
lo 3924 0 0 0 0 0 0 0 0
0 LRU

Output of ping 192.168.0.1:
***************************
PING 192.168.0.1 (192.168.0.1) from 192.168.0.2 : 56(84) bytes of
data.
From blockhead.junkyard (192.168.0.2): Destination Host Unreachable
(repeated another 35 times before being stopped with <Ctrl>-C)

--- 192.168.0.1 ping statistics ---
38 packets transmitted, 0 packets received, +36 errors, 100% packet
loss
Kernel filter, protocol ALL, datagram packet socket

Output of tcpdump -i eth0 (whilst being pinged by methuselah):
************************************************** ************
tcpdump: listening on eth0

0 packets received by filter

Change your Crossover cable or check your card setting for right media
connector(only if you have a RJ45 and BNC connector present on your
NIC). ifconfig output seems OK.It is a hardware issue.

Neeraj Gupta
(E-Mail Removed)

Paul wrote:
> Hi.
>
> I wonder whether anyone out there can help me. I'm new to networking,
> and have
> set up my first simple network by connecting two P100 linux boxes with
> an RJ-45
> crossover cable. The first of these machines, 'methuselah', is
> installed with a
> D-Link DE-220PCT jumperless NE2000-type card, and is running Slackware
> 9. The
> second, 'blockhead', is installed with an unidentified ISA
> RTL8019-based
> jumpered card, and is running Redhat 6.1. Both machines' LEDs come on
> when I plug in the crossover cable, and flickering on one end causes
> flickering at the
> other, but I can't ping properly between them. There seems to be a
> problem with
> blockhead - the RTL8019-based card seems unable to receive (and also
> seems to
> transmit in periodic bursts).
>
> I've disabled PnP in the BIOS on both machines, and have set the
> appropriate
> IRQ channels to Legacy ISA. I've also set the IO & IRQ jumpers on the
> RTL8019
> card to the correct settings, using a document (8019AS.pdf) I found on
> the
> RealTek website, but I didn't know what settings to use for the BROM
> jumpers,
> so I've left them unjumpered.
>
> Anyway, I include below the data from both machines (first before
> pinging, and
> then during pinging, both from blockhead to methuselah, and from
> methuselah to
> blockhead). If there's any further information I could provide that
> would be
> useful, please ask!
>
> I'd be very grateful for any help, as I've run out of ideas!
> Thanks,
>
> Paul.
>
> ************************************************** ****************************
>
> Data for methuselah (192.168.0.1)
> *********************************
>
> Relevant section (last few lines) of dmesg:
> *******************************************
> ne.c:v1.10 9/23/94 Donald Becker ((E-Mail Removed))
> Last modified Nov 1, 2000 by Paul Gortmaker
> NE*000 ethercard probe at 0x340: 00 40 05 2c 7d 3d
> eth0: NE2000 found at 0x340, using IRQ 10.
>
> Output of ifconfig:
> *******************
> eth0 Link encap:Ethernet HWaddr 00:40:05:2C:7D:3D
> inet addr:192.168.0.1 Bcast:192.168.0.255
> Mask:255.255.255.0
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:0 errors:0 dropped:0 overruns:0 frame:0
> TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:100
> RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
> Interrupt:10 Base address:0x340
>
> 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:0 errors:0 dropped:0 overruns:0 frame:0
> TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:0
> RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
>
> Output of netstat -r:
> *********************
> Kernel IP routing table
> Destination Gateway Genmask Flags MSS Window
> irtt Iface
> localnet * 255.255.255.0 U 0 0
> 0 eth0
> loopback * 255.0.0.0 U 0 0
> 0 lo
>
> Output of netstat -i:
> *********************
> Kernel Interface table
> Iface MTU Met RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP
> TX-OVR Flg
> eth0 1500 0 0 0 0 0 0 0 0
> 0 BMRU
> lo 16436 0 0 0 0 0 0 0 0
> 0 LRU
>
> Output of tcpdump -i eth0 (whilst being pinged by blockhead):
> ************************************************** ***********
> tcpdump: listening on eth0
> 18:20:50.374116 arp who-has methuselah.junkyard tell
> blockhead.junkyard
> 18:20:50.374230 arp reply methuselah.junkyard is-at 0:40:5:2c:7d:3d
> 18:21:00.372555 arp who-has methuselah.junkyard tell
> blockhead.junkyard
> 18:21:00.372658 arp reply methuselah.junkyard is-at 0:40:5:2c:7d:3d
> 18:21:10.370985 arp who-has methuselah.junkyard tell
> blockhead.junkyard
> 18:21:10.371113 arp reply methuselah.junkyard is-at 0:40:5:2c:7d:3d
> 18:21:20.369423 arp who-has methuselah.junkyard tell
> blockhead.junkyard
> 18:21:20.369532 arp reply methuselah.junkyard is-at 0:40:5:2c:7d:3d
>
> 10 packets received by filter
> 0 packets dropped by kernel
>
> Output of ping 192.168.0.2:
> ***************************
> PING 192.168.0.2 (192.168.0.2) 56(84) bytes of data.
> From 192.168.0.1 icmp_seq=1 Destination Host Unreachable
> (repeated another 23 times before being stopped with <Ctrl>-C)
>
> --- 192.168.0.2 ping statistics ---
> 26 packets transmitted, 0 received, +24 errors, 100% packet loss,
> time 25136ms, pipe 3
>
> ************************************************** ****************************
>
> Data for blockhead (192.168.0.2)
> ********************************
>
> Relevant section (last few lines) of dmesg:
> *******************************************
> ne.c:v1.10 9/23/94 Donald Becker ((E-Mail Removed))
> NE*000 ethercard probe at 0x340: 00 00 21 b1 82 08
> eth0: NE2000 found at 0x340, using IRQ 10.
>
> Output of ifconfig:
> *******************
> eth0 Link encap:Ethernet HWaddr 00:00:21:B1:82:08
> inet addr:192.168.0.2 Bcast:192.168.0.255
> Mask:255.255.255.0
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:0 errors:0 dropped:0 overruns:0 frame:0
> TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:100
> Interrupt:10 Base address:0x340
>
> lo Link encap:Local Loopback
> inet addr:127.0.0.1 Mask:255.0.0.0
> UP LOOPBACK RUNNING MTU:3924 Metric:1
> RX packets:0 errors:0 dropped:0 overruns:0 frame:0
> TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:0
>
> Output of netstat -r:
> *********************
> Kernel IP routing table
> Destination Gateway Genmask Flags MSS Window
> irtt Iface
> 192.168.0.2 * 255.255.255.255 UH 0 0
> 0 eth0
> 192.168.0.0 * 255.255.255.0 U 0 0
> 0 eth0
> 127.0.0.0 * 255.0.0.0 U 0 0
> 0 lo
>
> Output of netstat -i:
> *********************
> Kernel Interface table
> Iface MTU Met RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP
> TX-OVR Flg
> eth0 1500 0 0 0 0 0 0 0 0
> 0 BRU
> lo 3924 0 0 0 0 0 0 0 0
> 0 LRU
>
> Output of ping 192.168.0.1:
> ***************************
> PING 192.168.0.1 (192.168.0.1) from 192.168.0.2 : 56(84) bytes of
> data.
> From blockhead.junkyard (192.168.0.2): Destination Host Unreachable
> (repeated another 35 times before being stopped with <Ctrl>-C)
>
> --- 192.168.0.1 ping statistics ---
> 38 packets transmitted, 0 packets received, +36 errors, 100% packet
> loss
> Kernel filter, protocol ALL, datagram packet socket
>
> Output of tcpdump -i eth0 (whilst being pinged by methuselah):
> ************************************************** ************
> tcpdump: listening on eth0
>
> 0 packets received by filter

Paul,

I you have another crossover cable try that first.

Check both boxes to see if there's something in the firewall configuration
that may be blocking ICMP echo/reply messages. It would be unusual to block
those in a default firewall configuration.

Looking at the tcpdump it looks like the arp is working because it appears
blockhead is sending out arp requests. Methuselah can see the arp request so
transmission from blockhead to Methuselah seems to be working. Blockhead may
be blocked from receiving ICMP replies.

Bill in Sacramento, California
Land of the fruits and nuts...

> Change your Crossover cable or check your card setting
> for right media connector (only if you have a RJ45 and
> BNC connector present on your NIC). ifconfig output seems OK.
> It is a hardware issue.
>
> Neeraj Gupta
> (E-Mail Removed)

Thanks - I bought the crossover cable online, and I'm fairly confident that
it's all right (of course, I may be wrong). I suspect that the problem is with
the RTL8019 card. However, I don't know how to set it to use the RJ-45
connector rather than the coaxial one: I sort-of imagined that the card would
figure that out for itself, seeing that there's no BNC cable connected to it.
Anyway, thanks again for the suggestions.

Paul.

> Paul,
>
> I you have another crossover cable try that first.
>
> Check both boxes to see if there's something in the firewall configuration
> that may be blocking ICMP echo/reply messages. It would be unusual to block
> those in a default firewall configuration.
>
> Looking at the tcpdump it looks like the arp is working because it appears
> blockhead is sending out arp requests. Methuselah can see the arp request so
> transmission from blockhead to Methuselah seems to be working. Blockhead may
> be blocked from receiving ICMP replies.
>
> Bill in Sacramento, California
> Land of the fruits and nuts...

Thanks, Bill. I'm not sure that there are any firewalling measures at all in
place on blockhead, so - as you say - it's probably not that. I agree with
what you say about blockhead being somehow blocked from receiving. I've a
feeling that it's a hardware problem with the card, but I'll tinker with it a
bit more, and let you know if I get anywhere...
Thanks again,

Paul.

Ha!
Someone up there likes me - as a last-ditch attempt, I changed the
jumper settings on the card (they were configured correctly to work
with IRQ 10 and IO 0x340) to IRQ 11 and IO 0x280. And it worked!
Joy! Don't know why it made a difference - there were no hardware
conflicts reported, either in Linux or in W!?&@#s. Weird. Still, my
first network is up and running, so I'm happy.
Thanks again for the suggestions.

Paul.