On Tue, 23 Oct 2001, Tim Hockin wrote:
> So we've noticed, and taken issue with this behavior.
>
> If you have several IP aliases on an interface (eth0:0, eth0:1, eth0:2) you
> get inconsistent behavior when downing them.
>
> * if I 'ifconfig down' eth0:1, I am left with eth0:0 and eth0:2
> * if I 'ifconfig down' eth0:0, eth0:1 and eth0:2 go away, too
Use ip.
> I assert that this should not happen. I have a simple patch to fix this
> behavior, but I want to know a few things.
>
> * Is this supposed to happen? Why?
> * Is it correct that both the real interface and the first alias are marked
> as primary (! IFA_F_SECONDARY), while all other aliases are secondary? It
> seems to me that ALL ALIASES should be secondary. Is this wrong? Why?
iif - using ip then
ip addr add 10.1.1.1/24 dev eth0
creates 10.1.1.1 as a primary address for the 10.1.1.0/24 address space as
defined. Now:
ip addr add 10.1.1.2/32 dev eth0
10.1.1.2 in this case IS NOT a secondary alias because it is _not_ within
the scope of 10.1.1.0/24 by definition (it is in the scope of 10.1.1.2/32
by definition).
Now try:
ip addr add 10.1.1.3/24 dev eth0
and 10.1.1.3 is a secondary alias by definition as it is within the scope
of 10.1.1.0/24
Better yet:
ip addr add 10.1.1.4/25 dev eth0
This defines a third scope on dev eth0 and now:
ip addr add 10.1.1.5/25 dev eth0
defines 10.1.1.5 as a seconday within 10.1.1.0/25
So to summarize we now have:
Three (3) Primary addresses:
10.1.1.1 for scope 10.1.1.0/24
10.1.1.2 for scope 10.1.1.2/32
10.1.1.4 for scope 10.1.1.0/25
Two (2) Secondary addresses:
10.1.1.3 for scope 10.1.1.0/24
10.1.1.5 for scope 10.1.1.0/25
Now let us see what the interactions are:
ip addr del 10.1.1.1/24 dev eth0
Will wipe out both 10.1.1.1 and 10.1.1.3
Make sense now? BTW - don't use ifconfig and coloned addresses (which are
deprecated) as you will merely confuse yourself. Remeber that ifconfig =
InterFace CONFIGure which has everything to do with Interfaces and very
little to do with IP addresses... ;-}
> Can anyone fill me in?
RPDB documentation is your freind.
> Thanks
> Tim
> --
> Tim Hockin
> Systems Software Engineer
> Sun Microsystems, Cobalt Server Appliances
> thockin@sun.com
> -
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--------------------------------------------------
Matthew G. Marsh, President
Paktronix Systems LLC
1506 North 59th Street
Omaha NE 68104
Phone: (402) 932-7250 x101
Email: mgm@paktronix.com
WWW: http://www.paktronix.com
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This archive was generated by hypermail 2b29 : Wed Oct 31 2001 - 21:00:28 EST