Network Problem with 2 cards on the same subnet on Redhat

seb.its · 12-23-2005, 07:47 AM

Hello,
I have a network problem on Redhat ES v3.
I whish to have 2 network cards on the same subnet.
eth0 take traffic except the one from a specific subnet.
eth0 ip 192.168.1.1 mask 255.255.255.0
eth1 ip 192.168.1.2 mask 255.255.255.0
I have modified network routes configuration all 192.168.1 is on eth0 and access to default gateway too.
There is a route to 192.168.2.0/24 by eth1.
From a computer in 192.168.2.1 I wish to do a ssh session to 192.168.1.2. But it just work if I desactivate iptables.
If I activate iptables I see that ssh packet from 192.168.2.1 to 192.168.1.2 is denied because it's taken by eth0 insteed of eth1 (even if destination ip is the one of eth1).
How can I configure this to work ? (I think it could work isn't it ?).
A stange thing is when I desactivate iptables I can do a ssh session but if I let this session open and reactivate iptables it still work !! And it works even if I reboot the system !!
but the problem is that the next day (or a long moment after) the problem reappear.
thank you for any help
Seb

seb.its · 12-23-2005, 09:41 AM

Quote:

Originally Posted by PTrenholme

(Emphasis added.)

As to the poster's question, set.its, why do you want to put both cards on the same subnet? If you're using 192. for security, you could consider putting the other card on 90. instead. Or use two different subnet masks, say 255.255.127.0 and 255.255.128.0.

In fact this computer will be on a Firewall DMZ and I have just one subnet for this.
I know I can use only one card for this and all will be fine, but what I want to do is to separate the administration (via SSH) on a dedicated interface.