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To: Archie Cobbs <archie@whistle.com>
cc: freebsd-hackers@FreeBSD.ORG
Subject: Re: rtinit: wrong ifa 
In-reply-to: Your message of "Thu, 22 May 1997 16:31:20 PDT."
             <199705222331.QAA09008@bubba.whistle.com> 
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Date: Fri, 23 May 1997 05:04:44 +0100
From: Brian Somers <brian@awfulhak.org>
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> 
> I have a fairly recent RELENG_2_2 kernel. Suppose I want to number
> interfaces "lo1" and "ed0" like this:
> 
>   lo1: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
> 	  inet 207.76.205.82 netmask 0xffffffff 
>   ed0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
> 	  inet 207.76.205.82 netmask 0xffffff00 broadcast 207.76.205.255
> 	  ether 00:60:61:01:03:ec 

You're much better off setting up an alias on lo0 instead of config'ing
another lo.  You can do it with a GENERIC kernel (rc.conf even has an
example of this) and it dodges the rtinit error that you're seeing.

I actually do this for the source address of my tun0 interface.  It's
also my `hostname` IP address, and without it X has a couple of
problems !

> Huh? You want to know why the heck I'm doing this?? OK... :-)
> 
> The problem I'm trying to solve is that I want the address 207.76.205.82
> to always exist on *some* interface, because I've got services binding
> to it explicitly (as opposed to INADDR_ANY) -- but the "ed0" interface
> may be going up or down.
> 
> Remember that point to point interfaces gladly allow the local address
> to exist on another interface as well. This is the desired effect...
> 
> Some questions..
> 
>   Question #1:	Should this be allowed?

Yep.

>   Question #2:	Does FreeBSD allow this? It seems to work...

Yep.

>   Question #3:	Why does the following message appear on the console
> 		after ifconfig'ing lo1?
> 
> 		    rtinit: wrong ifa (0xf083b700) was (0xf07e7580)

'cos someone added it about a year ago to warn against conflicting
interfaces.  If you use a lo0 alias, this message doesn't appear.

>   Question #4:	Is it anything to worry about?

Loads, but it's not relevent to this discussion :)

> Thanks,
> -Archie
> 
> ___________________________________________________________________________
> Archie Cobbs   *   Whistle Communications, Inc.  *   http://www.whistle.com

-- 
Brian <brian@awfulhak.org>, <brian@freebsd.org>
      <http://www.awfulhak.org>
Don't _EVER_ lose your sense of humour....