traceroute reply in both incomming and outgoing interface

Hi there all,

I want my linux-box when i use traceroute to reply with both on my incomming
interface and my outgoing interface.

Now when i use traceroute my linux only responds once, and with the nearest
interface to me
Let's say eth0 10.0.0.10. But I want to also see wich outgoing interface it
uses. For instance eth1 xx.xx.xx.xx or eth2 yy.yy.yy.yy. So the same box has
to respond twice.
On a cisco router this is not a strange thing to do.
Is this possible on a Linux?

Thanks for your time

Jan-Willem

Jan-Willem Michels wrote:

>
> Hi there all,
>
> I want my linux-box when i use traceroute to reply with both on my
> incomming interface and my outgoing interface.
>
> Now when i use traceroute my linux only responds once, and with the
> nearest interface to me
> Let's say eth0 10.0.0.10. But I want to also see wich outgoing interface
> it uses. For instance eth1 xx.xx.xx.xx or eth2 yy.yy.yy.yy. So the same
> box has to respond twice.
> On a cisco router this is not a strange thing to do.
> Is this possible on a Linux?
>
> Thanks for your time
>
> Jan-Willem
Hi,

traceroute increases the time-to-live one-by-one to get one step further
each time. So you have to decrease the TTL twice.
iptables -t mangle -A PREROUTING -j TTL --ttl-dec 1
iptables -t mangle -A POSTROUTING -j TTL --ttl-dec 1

Never tried it before, though. ;-)
Alex