From: "Chris Buechler" <cbuechler at gmail dot com>
> On 4/12/06, Raylund Lai <raylund dot lai at kankanwoo dot com> wrote:
> > Hi,
> >
> > Is ip alias on WAN not recommended (on the online doc)?  Could I know
> > the reason?

> Because there is no need to do so, under normal operating
> circumstances.  Proxy ARP covers that.

> But, if your ISP needs an IP to ping, or something of that nature, you
> can enter an IP alias via exec.php.  Just run 'ifconfig fxp0 inet
> a.b.c.d netmask 255.255.x.x alias', replacing fxp0 with your WAN
> interface name, a.b.c.d with the IP address, and 255.255.x.x with the
> real subnet mask.  I would only recommend this on a temporary basis,
> and that will be lost on reboot.

I know this is ... bad plan ... bad network ... not recommended ... <Bad 
BOFH>
But it is also often highly useful, and frequently asked for.  I really 
think it should be in the FAQ.  Another case that often comes up is a remote 
office with an internal that "gets reset" to default, on a different subnet. 
This means a trip out, or a quick and dirty hack gone after a reboot. 
Hmmmm...

                        Lee