How to turn on IP forwarding?

[Ow Mun Heng]

On Thu, 2004-10-07 at 14:27, Jonathan Ryshpan wrote:
> I'm trying to make the machine amito forward packets from machine
> claremont to machine home.  Claremont pings amito and amito pings home,
> but claremont doesn't ping home.  All these machines are directly
> connected via ethernet claremont to amito on 192.168.10.x and amito to
> home on 172.16.0.x.  I have IP forwarding turned on in amito:
> 
> 	amito $ cat /proc/sys/net/ipv4/ip_forward
> 	1
> 

Okay.. IP forwarding is turned on.

> Claremont should have its gateway set up OK:
> 	claremont $ route
>         Kernel IP routing table
>         Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
>         192.168.10.0    *               255.255.255.0   U     0      0        0 eth0
>         169.254.0.0     *               255.255.0.0     U     0      0        0 eth0
>         default         amito.localdoma 0.0.0.0         UG    0      0        0 eth0
Cool. Default traffic which is not destined for local net is sent to the
gateway.
        
> and should know where home is:
> 
> 	claremont $ cat /etc/hosts
> 	# Do not remove the following line, or various programs
>         # that require network functionality will fail.
>         127.0.0.1		localhost.localdomain localhost
>         192.168.10.1		amito.localdomain amito
>         192.168.10.2		claremont.localdomain claremont
>         172.16.0.1		home home.localdomain
> 
> What have I missed?
Can you tell us what is the routing table on claremont? since amito can
ping home, it means there's connectivity.

But since claremont cannot ping home, this could mean several things.

1. Firewall? 
2. Wrong routing table.

> 
> BTW: What is the host 169.254.0.0 for?  How does it get into the routing table?

This is so-called zeroconf configuration. Google it up. I forget.
> Thanks - jon

-- 
Ow Mun Heng
Fedora GNU/Linux Core 2 on D600 1.4Ghz CPU kernel
2.6.7-2.jul1-interactive 
Neuromancer 15:08:52 up 5:48, 5 users, load average: 0.97, 0.68, 0.63