You don't need dummy ethN:N interfaces.  Use the iproute2 tools, 'ip' 
specifically.

ip link set eth0 down
ip address flush eth0
ip address add 1.2.3.4/24 brd + dev eth0
ip address add 1.2.3.5/25 brd + dev eth0
ip address add ....to your heart's content
ip link set eth0 up
ip route add default via 2.3.8.9 via 5.4.3.2 dev eth0

See the scripts on http://blue-labs.org/ for some examples.

David

Jim Roland wrote:

>I seem to remember back in either Kernel 2.0 or 2.2 there was a limit of 256
>aliases within the ethX aliasing (eg, eth0, then eth0:0 thru eth0:255).
>
>Has the limit on this been expanded with Kernel 2.4, is it stable and/or
>advised?  I have a need to bind more than 256 addresses to a single
>interface.  Without installing additional network cards.
>
>Thanks,
>Jim Roland, RHCE
>
>
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