hping multiple interface issue

Hi,

My setup is like this:

eth0 = 10.10.5.5/24
eth1 = 192.168.5.5/24

When i try to send a hping to a host via eth1:

/usr/sbin/hping 10.10.5.8 -1 -I eth1 -c 2

the ICMP requests go through eth0, but the ICMP reply is received on
the eth1 interface.
- How to forcibly send the packet via eth1?
- Is there a way to bypass the linux routing table?

TIA.

On 4 May 2004 17:01:23 -0700, data <(E-Mail Removed)> wrote:
> Hi,
>
> My setup is like this:
>
> eth0 = 10.10.5.5/24
> eth1 = 192.168.5.5/24
>
> When i try to send a hping to a host via eth1:
>
> /usr/sbin/hping 10.10.5.8 -1 -I eth1 -c 2
>
> the ICMP requests go through eth0, but the ICMP reply is received on
> the eth1 interface.
> - How to forcibly send the packet via eth1?
> - Is there a way to bypass the linux routing table?

Sounds like hping is not working per its man page. Either add the desire
route to 10.10.5.8 using dev eth1 (host route or using whatever gateway),
or read Adv-Routing HOWTO.

--
David Efflandt - All spam ignored http://www.de-srv.com/

(E-Mail Removed) (data) wrote in message news:<(E-Mail Removed) om>...
> Hi,
>
> My setup is like this:
>
> eth0 = 10.10.5.5/24
> eth1 = 192.168.5.5/24
>
> When i try to send a hping to a host via eth1:
>
> /usr/sbin/hping 10.10.5.8 -1 -I eth1 -c 2
>
> the ICMP requests go through eth0, but the ICMP reply is received on
> the eth1 interface.
> - How to forcibly send the packet via eth1?
> - Is there a way to bypass the linux routing table?
>
> TIA.

This is "standard" Linux behavior -- the IPs attach to the host (main
route table), not to the interface, so Linux uses the "handiest"
interface. You pinged 10.10.5.8/24 so it sent out through the
interface on the same subnet. But you told hping to use eth1 -- which
is where the reply came. Sounds like the handiest route to 10.10.5.8
was via the interface on 10.10.5.0 -- are you really surprised?

As D.E. suggests, look at the lartc howto and several others to get a
good picture of how Linux handles IP. It's possible to associate an
interface with a particular route table, but maintainence is no fun
unless you really need it. See policy routing.

hth,
prg
email above disabled