Re: 2 NIC cards not talking

pa3gcu
2004-01-21T16:38:22Z

On Wednesday 21 January 2004 16:23, Chadha, Devesh wrote:
> Juan,
>
> Eth0 has the external assigned IP by my ISP. Eth1 has a 192.168.x.x ip
> address. Eth1 acts as the DHCP server for my LAN. My LAN is working fine. I
> can connect machines to the LAN and even connect one machine to another.
>
> But I cannot get eth1 to talk to eth0. I cannot connect the LAN to the
> internet nor connect to any internal machine from outside!!

Then you need "masquerading", in otherwords iptables or ipchains.
Also make sure /proc/sys/net/ipv4/ip_forward is set to "1"

Something like the following for iptables;

#!/bin/sh

iptables --flush # Flush all the rules in filter and nat tables
iptables --table nat --flush
iptables --delete-chain #chains that are not in default filter/nat table
iptables --table nat --delete-chain

# Set up IP FORWARDing and Masquerading
iptables --table nat --append POSTROUTING --out-interface eth0 -j MASQUERADE
iptables --append FORWARD --in-interface eth1 -j ACCEPT

echo 1 > /proc/sys/net/ipv4/ip_forward # Enables packet forwarding by kernel
This is a must for both examples.

Or the following with ipchains.
/sbin/ipchains -A forward -s 192.168.11.0/24 -j MASQ
Change to suit your subnet.

> Do I need to bridge the 2 NICs ???

No.

> Regards,
> Devesh
>

--
If the Linux community is a bunch of theives because they
try to imitate windows programs, then the Windows community
is built on organized crime.

Regards Richard
pa3gcu@zeelandnet.nl