interface aliases

[Herta Van den Eynde]

On 11/05/07, Larry Brown <larry.brown at dimensionnetworks.com> wrote:
> Has anyone done any work where multiple applications use different
> aliases to a single ethernet card to talk to one another?  IE
>
> One application uses 10.10.10.1
> The next uses 10.10.10.2
> The last uses 10.10.10.3
>
> They are all:
>
> eth0:1
> eth0:2
> eth0:3
>
> One of the applications talks to another application as if it is on
> another box addressing messages to its IP address.
>
> For the most part this works fine.  I noticed that this process
> generates a lot of un-answered arp requests.  I don't know if I am
> playing with fire with this for some reason or the only ill affect is
> that these arp requests add unnecessary traffic.  Any thoughts?
>
> By the way, the reason for these apps talking to one another via IP is
> that sometimes those apps are offloaded to other systems and we don't
> want to have to change logic in communication.
>
> Larry

Hi Larry,

This is basically how unix/linux clusters work, but I must admit, I
never looked at the arp requests.

If the arps bother you, and you're not using this for clustering with
automatic failover, you could also manage this via dns or /etc/hosts
files.  You could create three hostnames, and simply have the names
translate to the ip address you want/need.

Kind regards,

Herta