Re: route change addr -ifp foo behaviour

[David Young <dyoung%pobox.com@localhost>]

On Tue, Mar 03, 2009 at 08:36:03PM +0000, Roy Marples wrote:
> Hi List!
> 
> ifconfig re0 alias 192.168.0.1/24 #re0 gets the connected route
> ifconfig re1 alias 192.168.0.2/24
> 
> Now, we want to change the connected route to re1
> 
> route change 192.168.0.0/24 -ifa 192.168.0.2
> route change 192.168.0.0/24 -ifp re1 -ifa 192.168.0.2
> route change 192.168.0.0/24 -ifp re1
> 
> What is the *expected* behaviour of the above three commands?
> I ask because in my mind they are equivalent when there is only one INET
> address on the interface, but the real world results are different.

Here are my expectations:

> route change 192.168.0.0/24 -ifa 192.168.0.2

Use the source address 192.168.0.2 for traffic originating from
this host with destination 192.168.0.0/24.

> route change 192.168.0.0/24 -ifp re1 -ifa 192.168.0.2

Use the source address 192.168.0.2 for traffic originating from
this host with destination 192.168.0.0/24; reach said destination
through re1. 

> route change 192.168.0.0/24 -ifp re1

Reach destination 192.168.0.0/24 through re1.

> ifconfig re0 -alias 192.168.0.1 # connected route remains, ok
> ifconfig re1 -alias 192.168.0.2
> 
> Now, if the last route style command is used, the last ifconfig command
> will not remove the connected route. If the other two where used (ifa
> specified) then the connected route is removed.

I don't know what to make of that.  It would help if you
would send relevant 'route show' or 'netstat -rn -f inet'
output at each step, so that readers don't have to try to reproduce
these steps on their own.

Dave

-- 
David Young             OJC Technologies
dyoung%ojctech.com@localhost      Urbana, IL * (217) 278-3933