[lug] ip aliasing with a 2.4 kernel

[Hugh Brown]

It turns out that if you add a DEVICE line to the cfg file it works
fine, if you don't it tries to use linuxconf.

Sheepishly yours,

Hugh


On Wed, 2002-02-20 at 11:25, Hugh Brown wrote:
> Nothing like relying on someone else's stuff without taking the time to
> do it right.
> 
> In the past, I have just added the ifcfg-eth0:n and things just worked
> when I did a 'service network start'
> 
> I tried it again on a rh machine with 2.4 and it didn't work anymore.  I
> had read the comment that things were being changed from 2.2 to 2.4 and
> assumed that this was what was happening.
> 
> I went playing/prodding again just now and discovered that the redhat
> scripts require linuxconf (which I abhor and routinely remove after
> installing a new system) in order to the aliasing right if you just use
> the rc network script to start it up.
> 
> I tried the right incantation of ifconfig and it worked fine.  Now I am
> going to see if I can't fiddle with the ifcfg-eth0:n file a little so
> that the rc script will work even without linuxconf
> 
> Hugh
> 
> 
> On Tue, 2002-02-19 at 20:40, Chip Atkinson wrote:
> > I've used the old 2.2 commands pretty successfully and I believe it was on
> > 2.4.17 as well.  You can also put in aliases in
> > /etc/sysconfig/network-scripts/ifcfg-eth0:n where n is the alias number.
> > The weird thing about putting it in these scripts though is that you don't
> > get an address for the "real" interface.  I didn't spend too much time
> > playing with it, but it didn't look like you could.
> > 
> > Good question about the arp.  I believe that there is an arp cache, but
> > you'd think that the destination in the IP header wouldn't match and the
> > packet would be ignored.
> > 
> > 
> > Chip
> > 
> > On 19 Feb 2002, Hugh Brown wrote:
> > 
> > > I'm trying to figure out how to do ip aliasing under the 2.4 kernel.
> > > There is a mini how to that says the 2.2 method has been replaced by a
> > > new powerful method in 2.4 but doesn't say what it is.  It looks like
> > > the ip command is my friend but I can't find any good documentation for
> > > it.
> > >
> > > I tried something earlier and got some complaints.  I just tried it
> > > again and it seems to have worked.
> > >
> > > I'll send this anyway, because I found it useful and I hope someone else
> > > will (and that my epiphany won't be a "well, duh" for everyone else).
> > >
> > > The command I used was
> > >
> > > ip addr add 192.168.0.7/24 broadcast 192.168.0.255 dev eth0
> > >
> > > Anyone know of a slick way to make this part of the startup process
> > > (e.g. something in /etc/sysctl.conf or similar)?
> > >
> > > Okay, I played a bit more and then decided I was done so I deleted the
> > > new address assignment.  The problem is that it still responds to ping
> > > and if I ssh to the box it takes me to the right place (i.e. the machine
> > > that I had previous assigned the address to).  What gives?  Is there an
> > > arp cache somewhere that I have to wait for it to timeout?
> > >
> > > Hugh
> > >
> > >
> > >