ping problem two ethernet boards

Seck (seck@e-technik.fh-muenchen.de)
Wed, 29 Jan 1997 13:48:46 +0100


Help...Help....Help.....

Hi all,

i have a linux server running 2.0.25 with two SMC-etherboards: eth0 and
eth1.

Who has experience in configuring eth0 and eth1 SMC-boards connecting two
subnets via one server running linux 2.0.2x with static routing?

The computers connected to eth1 are not reachable by pinging from the
linux-server!! (eth1/0 inside!) and vice versa.

My task:
My linux server should run as static router between rest of world an two
other computer say: A and B.
I put into the server two SMC-boards (made up lilo.conf :append...eth1 ) an
configured them as eth0 und eth1 .
(Class C Netz)

My hardware is running:

Running ifconfig following appears:

eth0: IP aaa.aaa.aaa.73 netmask 255.255.255.0
broadcast aaa.aaa.aaa.255

eth1: IP: aaa.aaa.aaa.73 netmask 255.255.255.0
broadcast aaa.aaa.aaa.255

computer A IP:aaa.aaa.aaa.74 connected to eth1
computer B IP:aaa.aaa.aaa.75 connected to eth1
nothing connected to eth0 so far!!

!!!!!!!!!!!I first tried:

route add -net aaa.aaa.aaa.0 netmask 255.255.255.0 eth1
route add default gw aaa.aaa.aaa.254 eth1
route add -host aaa.aaa.aaa.74 eth1
route add -host aaa.aaa.aaa.75 eth1

no routing table entries for eth0!!

ping aaa.aaa.aaa.74 oder .75 time-out
Computer A and B pinging linux-server aaa.aaa.aaa.73 time out.

ifconfig shows receive-errors as resonse to transmit pakets on eth1
tcpdump -i eth1 shows only .74/.75 should be reached
arp -a shows HW Adress 0000000000000 for ip aaa.aaa.aaa.74 and .75 ... the
ethernet-adress of .74 and .75 computer is not returned?!

Why??Error....................!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!

!!!!!!!!!!!!!!!!!!!!!Second try:

moving the computer aaa.aaa.aaa.74 and .75 to eth0
nothing connected to eth1.
Changing then the route commands to:

route add -net aaa.aaa.aaa.0 netmask 255.255.255.0 eth0
route add default gw aaa.aaa.aaa.254 eth0
route add -host aaa.aaa.aaa.74 eth0
route add -host aaa.aaa.aaa.75 eth0

no entries in routing-table for eth1!!

then pinging from/to computer aaa.aaa.aaa.74/.75 works
fine.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

The SMC-boards are ok regarding IRQs , I/O and other adresses.
Both are working. Changing configuration changing eth0 to eth1 and retry
eth1 ...same result eth1 doesnt works.

I read the /usr/doc/howtos network admin guide.. ??? I am desperate because
i promised my task could be done by linux and therfore ....

What did I wrong? What can I look for??

I would be glad to get some guesses from evryone what I can try to get
close to the root of the problem!

Thanks

Rainer Seck