IP Fowarding in Red Hat

Hi all,
I'm having some problem in IP FORWARDING in Red Hat.
My network is as follows:

winXP -----------------------eth1---------------eth0-------------SUN
SERVER
172.16.10.2 172.16.10.1 172.16.2.10
172.16.2.1
255.255.255.0 255.255.255.0 255.255.255.0
255.255.255.0
GW:172.16.10.1 GW:172.16.2.1


eth1 and eth0 are the 2 LAN cards of my Linux machine which I would
like to use as a gateway for the 172.16.10.x network. I have enabled
IP forwarding in that machine by putting:
1. echo "1" > /etc/sys/net/ipv4/ip_forward in
/etc/rc.d/rc.local. I have verified it by using
sysctl -a | grep ip.for which shows
net.ipv4.ip_forward=1

2. my /etc/sysconfig/network file is
NETWORKING=yes
GATEWAY=172.16.2.1
FORWARD_IPV4="yes'
GATEWAYDEV="eth0"

The problem is that the LINUX box is not forwarding packets going out
of the WIN-XP machine to the SUN SERVER.

If I do a tracert from the WIN-XP it shows that the packet reaches
upto 172.16.10.1 i.e. the eth1 of the linux machine but don't go
beyond that. I can even ping to the other interface
card(eth0:::172.16.2.10) of the LINUX box from WIN-XP.

The whole purpose of this design is to use some software in the SUN
SERVER from the WIN-XP Clients.

I wonder what may be the reason ? Can anyone please show me a way ?

thanks in advance

regards
bhaskar.

Baruah wrote:

> winXP -----------------------eth1---------------eth0-------------SUN
> SERVER
> 172.16.10.2 172.16.10.1 172.16.2.10
> 172.16.2.1
> 255.255.255.0 255.255.255.0 255.255.255.0
> 255.255.255.0
> GW:172.16.10.1 GW:172.16.2.1

Eurgh. Linewrap and non-proportional font broke the figure, but I'll try to
figure out...

So, does the GW: 172.16.2.1 mean that in the Sun server you have set the
default gateway to 172.16.2.1? If so, change it to 172.16.2.10 (if it is the
Linux box's address?)

> The problem is that the LINUX box is not forwarding packets going out
> of the WIN-XP machine to the SUN SERVER.

What does 'route -n' say (in the Linux box)?

> If I do a tracert from the WIN-XP it shows that the packet reaches
> upto 172.16.10.1 i.e. the eth1 of the linux machine but don't go
> beyond that. I can even ping to the other interface
> card(eth0:::172.16.2.10) of the LINUX box from WIN-XP.

Hmm. So Sun isn't returning the packets. What does Sun's route table look like?

> The whole purpose of this design is to use some software in the SUN
> SERVER from the WIN-XP Clients.

> I wonder what may be the reason ? Can anyone please show me a way ?

You don't happen to have any firewalls in place?

-Timo

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