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Date:      Mon, 12 Feb 2007 15:27:14 -0200
From:      JoaoBR <joao@matik.com.br>
To:        freebsd-stable@freebsd.org, kevin@insidesystems.net, brooks@freebsd.org
Subject:   Re: Desired behaviour of "ifconfig -alias"
Message-ID:  <200702121527.15246.joao@matik.com.br>
In-Reply-To: <200702121426.l1CEQIF4031564@lurza.secnetix.de>
References:  <200702121426.l1CEQIF4031564@lurza.secnetix.de>

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On Monday 12 February 2007 12:26, Oliver Fromme wrote:
> JoaoBR <joao@matik.com.br> wrote:
=2E...
>  > "ifconfig nic -alias" is obviously a wired and confusing behaviour
>
> It might be confusing to you.  Personally I think that the
> current behaviour isn't that far off.
>

the question is not you or me, I guess that you are like me perfectly capab=
le=20
of working around messed things. But that does not make it being right or=20
acceptable.


> First you need to be aware that there is no distinction
> between a primary IP and alias IPs (such a distinction
> existed historically, but it's gone).  All of the IPs on
> an interface are equal, just like hardlinks on a file.

I said this in shorter words in my post but it is not the point at all.=20

> The "-alias" parameter simply removes an address from an

man page tells us that it removes THE specified address ... not AN address

> interface.  The term "alias" should really be avoided
> because it is misleading.  You can use "delete" or "remove"
> which do the same thing.  I think "-alias" should really
> be regarded to exist for backwards compatibility only.
> Personally I always use "delete".
>


it is not misleading and it is a perfect term. With alias you add secondary=
=20
addresses to an interface. Like secondary is probably the better word, as=20
cisco does, but what we have is alias and that is ok. It could be any other=
=20
word so long as it works as it should. (We do have "add" also I remember.)


also don't forget the following, alias is a perfect and usual term, then wh=
en=20
I can add an IP address with the alias cmd then -alias should remove it.

I know that I can add the first IP also with alias but that is not the usua=
l=20
way.

 Also do not forget that the usual way since ever is ifconfig_nic_alias0 to=
=20
add one. So this thing is confusing.


> If no IP address is specified, then it's not completely
> nonsensical to remove the first address.  In fact I've
> used that short-cut to quickly remove the only address
> from an interface.  I've used "ifconfig xyz0 delete"
> quite a lot.

the man page tells us that -alias removes *the* specified address and not t=
he=20
first, also the man page does not say that there is any further action when=
=20
*no* IP address specified

delete is according to the man page another word for -alias, that means, us=
ing=20
grammatical logic that -alias is the main command, then according to the ma=
n=20
page there is no other command as "-alias *IP*" to remove an IP address=20
and -alias only should not remove anything


>
>  > then already beeing here there is more, ifconfig nic alias does not
>  > return anything at all
>
> That's the same as "ifconfig nic add".  If you don't tell
> it anything to add, then it won't add anything, of course.
> Remember that UNIX always tries to do exactly what you
> tell it to dao.  ;-)
>

you see, now you apply logic because you want to and when not not ... ;)

to let it more clear what I mean, you say: "you don't tell it anything to a=
dd"=20
so why the heck "ifconfig nic -alias" should remove one if I do not tell so?


>  > and ifconfig nic -alias on a nic w/o ip returns "can't assign
>  > requested address" ...
>
> That error corresponds to EADDRNOTAVAIL, which is the
> correct errno to return, because there's no address left
> on the interface.  However, I agree that the message is
> a bit confusing to the unfamiliar.

at least one agreement here :)

=2D-=20

Jo=E3o







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