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Date: Thu, 10 Oct 1996 15:03:15 -0700
From: Julian Elischer <julian@whistle.com>
Organization: Whistle Communications
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To: Nate Williams <nate@mt.sri.com>
CC: "Eric J. Chet" <ejc@gargoyle.bazzle.com>,
        Ollivier Robert <roberto@keltia.freenix.fr>, hackers@freebsd.org
Subject: Re: IP ALIASING
References: <199610101644.SAA25875@keltia.freenix.fr>
		<Pine.BSF.3.95.961010144443.28346A-100000@gargoyle.bazzle.com> <199610101851.MAA16619@rocky.mt.sri.com>
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Nate Williams wrote:
> 
> >       Why does this not work with ppp0 under -current?
> >
> > >ifconfig ppp0 alias 206.103.246.162 netmask 0xffffffff
> > >ifconfig: ioctl (SIOCAIFADDR): Destination address required
> 
> I'm guessing point-point links like sl0/ppp0 require two addresses.  I
> don't think you can alias point-point links, but Bill and/or Garrett
> would be better qualified to answer.
> 
you can alias a P2P link if (and only if)
the LOCAL address is differnt.....

e.g.p0: flags=8010<POINTOPOINT,MULTICAST> mtu 1500
        inet 1.1.1.1 --> 2.2.2.2 netmask 0xff000000 
        inet 3.3.3.3 --> 2.2.2.2 netmask 0xff000000 
of course this is stupid to hav ehte remote addresses the same,
except possibly for multi-link ppp.
but that is achieved differntly anyhow..
making Both addresses differnt also workd..
p0: flags=8010<POINTOPOINT,MULTICAST> mtu 1500
        inet 1.1.1.1 --> 2.2.2.2 netmask 0xff000000 
        inet 3.3.3.3 --> 4.4.4.4 netmask 0xff000000 
what DOESN'T work and should 
is the following:
p0: flags=8010<POINTOPOINT,MULTICAST> mtu 1500
        inet 1.1.1.1 --> 2.2.2.2 netmask 0xff000000 
        inet 1.1.1.1 --> 4.4.4.4 netmask 0xff000000 
which would be really useful for FRAME RELAY interfaces.

> Nate