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From: "Patrick O'Reilly" <bsd@perimeter.co.za>
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Date: Wed, 25 Jun 2003 14:26:20 +0200
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Subject: Alias on loopback interface???
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Hi folks.

I'd appreciate any comments on the pros and cons of configuring an alias
IP on the loopback interface.  I've tried it and it works OK, but
perhaps there are repercussions that have not occurred to me.

Why?  Well I have a number of BSD gateways, each of which has numerous
interfaces, and I am forever confusing myself about which IP address
really identifies that box.  I am planning to set assign each box a
unique IP for my internal admin purposes, but then got to wondering
which interface is most suitable to carry this new alias.  That's when I
though - Hey - why not use lo0 ?

I do run ipf/ipnat and ipfw/DUMMYNET on many of these.  Clearly I will
need to make provision for this unusual traffic on the lo0 interface
too.

Of course, the IPs I intend using will be RFC1918 compliant private
addresses.

Thanks for any comments.

Regards,
Patrick.