Proxy ARP with Linux

Hi,

I read http://www.sjdjweis.com/linux/proxyarp/, whose content came
from this group, and would like to ask who followed this thread (or
someone else) if is it possible to set up proxy arp and IP alias
together.

My provider gave me hosts 150.218.62.128-191 (mask: 26bits). I'd like
to set up proxy arp in the linux and ip alias in it internal interface
for reach net 192.168.0.0 and proxyarp'ed laptop. So, I need not to
install another NIC on Linux.


NET-ROUTER (X.Y.Z.129) -------- (.130) Linux (192.168.0.1)
-----------------------(192.168.0.2-254) LAN

|

|

(X.Y.Z.131) Laptop


Thank you
Tom

Better squema:


NET-ROUTER
|
|
LINUX
|
|---------Laptop
|
Lan

On 26 Apr 2006 15:18:22 -0700, "Tom" <(E-Mail Removed)> wrote:

>
> Hi,
>
> I read http://www.sjdjweis.com/linux/proxyarp/, whose content came
>from this group, and would like to ask who followed this thread (or
>someone else) if is it possible to set up proxy arp and IP alias
>together.

Yes.

But!!! ProxyARP can be a terrible mess using Weiss' setup. Your
routing tables must be PERFECT else your box will return IS AT for
stuff it has no business claiming.

> My provider gave me hosts 150.218.62.128-191 (mask: 26bits). I'd like
>to set up proxy arp in the linux and ip alias in it internal interface
>for reach net 192.168.0.0 and proxyarp'ed laptop. So, I need not to
>install another NIC on Linux.
>
>
> NET-ROUTER (X.Y.Z.129) -------- (.130) Linux (192.168.0.1)
>-----------------------(192.168.0.2-254) LAN
>
> |
>
> |
>
> (X.Y.Z.131) Laptop
>
>
> Thank you
> Tom
I don't think much of either of your diagrams, and you really have not
given enough information for a good answer. From what I see, you just
need the external interface to have IPs .129 and .130 (alias). What
is not clear is why you need anything other than the correct netmask
for the internal IF.

You might get some ideas from
http://yesican.chsoft.biz/lartc/index.html

in EXAMPLES the 4th line down is the place to start.
--
buck

"buck" <(E-Mail Removed)> escreveu na mensagem
news:(E-Mail Removed)...
> I don't think much of either of your diagrams, and you really have not
> given enough information for a good answer. From what I see, you just
> need the external interface to have IPs .129 and .130 (alias). What
> is not clear is why you need anything other than the correct netmask
> for the internal IF.

my internal netmask é 24bits.

>
> buck

My Linux server (eth0=10.0.0.130; eth1=192.168.0.1) is connected to
internet via cisco router (10.0.0.129) and to Lan via eth1. I just want
to connect a machine to the Lan switch (so, it will physically access
eth1, internal IF) and configure it to IP 10.0.0.131, as it were in the
external segment.


Internet ------ | eth0-LINUX-eth1 | ------LAN

10.0.0.128/26 192.168.0.0/24


alias:
eth1:0 = 10.0.0.130

Is these routes right?
ip route del 10.0.0.128/26 dev eth0
ip route del 10.0.0.128/26 dev eth1
ip route add 10.0.0.131 dev eth1
ip route add 10.0.0.128/26 dev eth0



Tom

Internet ------ | eth0-LINUX-eth1 | ------LAN

10.0.0.128/26 192.168.0.0/24


eth0=10.0.0.130
eth1=192.168.0.1
eth1:0=10.0.0.130


This script worked:
##
net_ext="10.0.0.128/8"
if_ext="eth0"
if_int="eth1"
ip_if_int="10.0.0.130"
ip_client="10.0.0.131" # Laptop

ifconfig $if_int:0 $ip_if_int up

echo 1 > /proc/sys/net/ipv4/conf/$if_int/proxy_arp
echo 1 > /proc/sys/net/ipv4/conf/$if_ext/proxy_arp

ip ro del $net_ext dev $if_int
ip ro del $net_ext dev $if_ext
ip ro add $ip_client dev $if_int
ip ro add $net_ext dev $if_ext
##


Thank you =)


Tom