Subject: Re: CVS commit: src/sys
To: Jonathan Stone <>
From: Matt Thomas <>
List: tech-kern
Date: 12/06/2004 13:53:43
At 01:44 PM 12/6/2004, Jonathan Stone wrote:
>In message <29627.1102368412@munnari.OZ.AU>Robert Elz writes
> >No, you're debating a different question.
>I don't think so. I'm not even sure if multiple-loopback devices was a
>deliberate design decision, or if it predates the functional/semantic
>  split of`needs-count' vs. ``needs-flag''.
>I've also seen no rationale for multiple loopback devices, given that
>a single loopback device can support multiple addresses for a given
>family.  Christos guessed at a couple of possible uses, but they make
>no technical sense. (Link aggregation, for example, requires so much
>additional effort that it makes no sense at all to lump it in with a
>loopback device).

Actually, multiple loopback devices can be useful for tcpdump or
just keeping statistics.  It'd be nice if you set a loopback device
as a null interface.  (ifconfig lo1 media null)  Then you have an
easy to collect counters.  (you could do the same with a reject mode).

Matt Thomas                     email:
3am Software Foundry              www:
Cupertino, CA              disclaimer: I avow all knowledge of this message.