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Need some help with a Linux Router....

E

Electric Amish

Elite Member
Here's the situation. I have Redhat 6.2 installed on a system with (2) 3com 3C905C network cards in it. I have both eth0 and eth1 activated on boot. eth0 has an IP address of 192.168.111.4 (the same as one side of our network). eth1 has an IP address of 10.10.10.1 (the same as the other side of our network). I'm trying to get the 192.168.111 and the 10.10.10 networks to talk to each other.

I've tried setting up several different configuations in the netcfg screen, but nothing seems to work. I can get to the 192.168.111 network from the linux box. I can ping the 192.168.111.4 from the 192.168.111 network. I cannot ping the 10.10.10.1 NIC from either side of the network.

Can someone out there give me some pointers???

thanks,

amish
 
cat /proc/sys/net/ipv4/ip_forward Should be a "1" in there.

If it's a "0", then just echo 1 > /proc/sys/net/ipv4/ip_forward to make it so.

Also make sure that you're using the same netmask on the 10.x.x.x network. Can you ping the 10.x.x.x card by IP on the Linux box?
 
Ok try ifconfig -a and see if both eth cards are "UP" and working. If indeed they are then make sure the subnet mask's are right. Its odd that the 10.10.10.x scheme isnt able to ping so I would suspect that the card isnt on or not functioning. Once you have both eth's working and able to ping then you will need to create the proper routing table and ip_forward enabled.(like what damaged just pointed out) But first things first, is eth1 UP?


SHUX
 
Both cards are up. Both show up correctly in ifconfig.

I can ping both the 192.168.111.4 and 10.10.10.1 cards locally.

Both netmasks are 255.255.255.0.

amish
 


<< I can ping both the 192.168.111.4 and 10.10.10.1 cards locally. >>


How about from either side of the router from a client on that segment? And what is eth0 connected to? what is eth1 connected to, are those devices working?


SHUX
 
eth0 is connected to a hub. eth0 can be pinged from computers in the 192.168.111.x segment.

eth1 is connected to another computer (address 10.10.10.2/255.255.255.0). eth1 cannot be pinged by anything other than the linux system in which it resides. I also cannot ping the 10.10.10.2 computer.

The table in netcfg looks like so:

Default gateway: 192.168.111.1 (our gateway)
Default gateway device: eth0

INTERFACE/NETWORK ADDRESS/MASK/GATEWAY

eth0/192.168.111.0/255.255.255.0/192.168.111.4
eth1/10.10.10.0/255.255.255.0/10.10.10.1
any/127.0.0.0/255.0.0.0/0.0.0.0


The ip_forwarding was 0, I ran the cat and changed it to 1. Still haven't got it working. 🙁

thanks for the help.

amish

 


<< eth1 is connected to another computer (address 10.10.10.2/255.255.255.0). eth1 cannot be pinged by anything other than the linux system in which it resides. I also cannot ping the 10.10.10.2 computer. >>


Are you using a crossover cable to connect the two computers? that could be the problem, also you might want to add the echo &quot;1&quot; cat /proc/sys/net/ipv4/ip_forward to your rc.local file so you don't have to type that in everytimje you boot. 🙂. what about route? what is the output of route?


SHUX
 
You have link right? Check and/or replace the wiring. Are you sure the other NIC works? My understanding here is that you're directly connecting two NICs right? It is a cross-over cable b/w those two cards correct? If it ain't, it ain't gonna work.
 

have you added a default route for all 10.10.10.x packets on the 192.168.111.x side and a default route for the 192.168.111.x packets on the 10.10.10.x side?

 
Dude! I bet that's it. (crossover cable)

We got it so stuff on the 192.168.111.x side of the network could ping the 10.10.10.2 computer, but the 10.10.10.2 computer couldn't ping out to anywhere. So, I bet it needs a crossover cable since it's not connected through a hub!

Damn!!! Can't tell you how many times I've been screwed by that scenario! 😉

Thanks for all the help.

I'll work on it some more tomorrow.

thanks!!!!

amish
 
Yeah! Now, after you do that we can fsck with the routing table a tad. No biggee really on that one.

bubba, why don't you need that entry? Directly connected that's why. 🙂
 
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