Hi. I have a Linux box in the middle of 2 Network Segments.NetworkA and NetworkB.



NetworkA------------->eth0 LINUX eth1 -------->NetworkB

NetworkA: 192.168.35.X
Eth0: 192.168.35.20
Eth1: 192.168.35.21
NetworkB: 192.168.35.X

I want networkA to be able to access NetworkB.At the moment i Can't ping any PC on NetworkB.

Things i Trierd:

I can ping Eth0 from Network A, but only if i Disable Eth0 can i ping NetworkB from the linux box.

FROM WINDOWS: ping 192.168.35.20 "REPLY 100%"
FROM WINDOWS: ping 192.168.35.21 "REPLY 100%"

FROM LINUX:eth0 ping 192.168.35.X "REPLY 100%"
FROM Linux:eth1 ping 192.168.35X "NO REPLY"

If i disable Eth0: ifconfig eth0 down
FROM LINUX: eth1: ping 192.168.35.X "REPLY 100"

Why must i first disable eth0 to be ably to ping from eth1 to networkB?

This is not my biggest Issue: I want to be ably to communicate from NetworkA to NetworkB.

PLEASE HELP.........

Where you mention 'Network Segments' - you don't mean subnets do you? That setup isn't going to work without proxying the arp packets on each segment, assuming your linux box is the only piece of equipment between A and B.

Otherwise, if you actually do mean subnets, then you need to put each interface into *actual* subnets - 192.168.35.20 and 192.168.35.21 are in the same network - no matter what netmask you use Try splitting it out into 192.168.35.0/27 and 192.168.35.32/27 for eth0 and eth1 respectively, then just forward between the subnets (with routes as required pointing to the linux box)

What's the topology - is everything connected into the same hub or switch (or a cluster thereof)?

I've got yet to understand what you call a segment... Referring to the IP layer, your 2 eth look furiously to me like they are on the *same* segment (but of course I could be mistaken, since you don't give the netmask). Referring to physical segments, a switch is what you need, not a router.

Looks to me, the first thing to do is to define properly your 2 networks :
Network A : 192.198.35.0 -> eth0 192.190.35.20/24 (or 192.190.35.20/255.255.255.0)
Network B : 192.198.36.0 -> eth1 192.190.36.20/24 (or 192.190.36.20/255.255.255.0)

Re-configure accordingly the PCs in Network B, of course.

Then routing will have to be configured on your multihomed Linxu box...

Good luck !