route (is it forwarding packets?) (sorry if duplicate).

[Jeff Vian]

On Wed, 2004-08-25 at 16:14, Les Mikesell wrote:
> On Wed, 2004-08-25 at 16:02, Jeff Vian wrote:
> > > And if anyone
> > > is listening that might fix this, please also add a straightforward
> > > way to control the source address used for outbound connections when
> > > a machine is given multiple addresses on the same subnet for virtual
> > > hosting.
> > > 
> > >
> > if your system has several IP addresses added as aliases on a single
> > interface/subnet, the routing table will provide the 'source' addresses
> > for outgoing communications.
> > 
> > if for example you have 4 IP addresses assigned as follows
> >    eth0      192.168.2.1
> >    eth0:1    192.168.2.2
> >    eth0:2    192.168.2.3
> >    eth0:3    192.168.2.4
> > 
> > Then the routing table will work as:
> > 
> > 192.168.2.0     *     255.255.255.0   U     0      0        0 eth0
> >    the source will be 192.168.2.1
> > 192.168.2.0     *     255.255.255.0   U     0      0        0 eth0:1
> >    the source will be 192.168.2.2
> > 192.168.2.0     *     255.255.255.0   U     0      0        0 eth0:2
> >    the source will be 192.168.2.3
> > 
> > etc.
> 
> Suppose you originate a connection to another network and
> your router is at 192.168.2.254.  Any of those addresses would
> work as the source.  Does it pick the 1st, last, or at random?

NOTE:  I specified what had to be in the routing table, and AFAIK only
one of those can be there.

I believe that any config except the first would require some manual
manipulation of the routing table.

> There was a variable called NOALIASROUTING in the config files
> when I looked long ago but I never found any documentation
> about what it was supposed to do or if there was a way to set
> it other than mucking around in the stuff under /etc/sysconfig.
> 

That option would prevent the config I mention above and AFAIK would
ensure the source would always be the default base device IP.

> ---
>   Les Mikesell
>     les at futuresource.com
> 
>