[CentOS] Sending traffic through Secondary IP Address

Dennis Gilmore dennis at ausil.us
Mon Mar 5 20:19:23 UTC 2007

On Monday 05 March 2007 02:09:21 pm Al Sparks wrote:
> I have set up a secondary IP address in the same network as my primary.
> So
>    eth0: netmask
>    eth0:0 netmask
> And indeed when I invoke an apache instance that listens on the secondary
> IP address/interface it works, and it also makes it outside the LAN since
> the default gateway is defined in the routing tables for
> But I'd like to be able to send out some sort of broadcast on the network
> from that secondary interface so that the arp tables on various devices on
> the network get updated.
> How would I, say, use nmap to do something like that?  Is there a generic
> way to force a particular program to use a secondary IP address instead of
> the default primary?
> Obviously, something like BIND or Apache httpd has that hardcoded in so
> that you can tell them to use secondaries via their configuration files.
> But how about those programs that don't?
ping -I <destination>

ping -I eth0:0 <destination>

-I tells ping what interface to send the packet out 

Dennis Gilmore, RHCE

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