loopback with netmask 255.255.255.255 visible for all network

Hi all,

I have many virtual machines on a host and another server in the same
network 10.0.0.0/24.
One of the virtual machine has IP address/24 on eth0 and additional IP
in the same network, but with mask 32

ifconfig eth0 10.0.0.1 netmask 255.255.255.0 up
ifconfig lo:1 10.0.0.2 netmask 255.255.255.255 up

What can be the reason I can see 10.0.0.2 from external host?


___
Thanks in advance,
Artur

Hello,

Artur Kaminski a écrit :
>
> ifconfig eth0 10.0.0.1 netmask 255.255.255.0 up
> ifconfig lo:1 10.0.0.2 netmask 255.255.255.255 up
>
> What can be the reason I can see 10.0.0.2 from external host?

Linux enforces what is called the "weak model". this means that any
local address assigned to any interface is reachable on any interface.
In other words, addresses are globally assigned to the host rather than
specific interfaces. The only exception is the range 127.0.0.0/8, not
because it is assigned to the loopback interface but because it is
prohibited outside a host.

On Jun 3, 11:06 pm, Pascal Hambourg <boite-a-s...@plouf.fr.eu.org>
wrote:
> Hello,
>
> Artur Kaminski a écrit :
>
>
>
> > ifconfig eth0 10.0.0.1 netmask 255.255.255.0 up
> > ifconfig lo:1 10.0.0.2 netmask 255.255.255.255 up
>
> > What can be the reason I can see 10.0.0.2 from external host?
>
> Linux enforces what is called the "weak model". this means that any
> local address assigned to any interface is reachable on any interface.
> In other words, addresses are globally assigned to the host rather than
> specific interfaces. The only exception is the range 127.0.0.0/8, not
> because it is assigned to the loopback interface but because it is
> prohibited outside a host.

Thanks Pascal,

I try to find why it stopped on one machine only while I have four
(two loadbalanced pairs of servers).



Regards
Artur