Re: trouble setting up routing

Dear Jim,


It is possible to have multiple default routes on a system. This
works for us since long (AFAIR from Solaris 7 on). 

Which path is selected for outbound packets is determined by the
IRE (the internal IP routing entry).

For instance, if you have two interfaces, say hme0 and hme1, you
can view the routing entries for each of the interfaces by

   # netstat -ra | grep hme0   (or hme1)

The output looks like:

Routing Table:
  Destination           Gateway           Flags  Ref   Use   Interface
-------------------- -------------------- ----- ----- ------ ---------
tarox4.mbi-berlin.de     --                UHA      1    119  hme1


That is, a host route pointing to that host 'tarox4' ist installed
for interface hme1.


The mechanism on how the outbound interface is selected is determined
by the variable 'ip_enable_group_ifs'. It can be set by
   
   # ndd /dev/ip
   name to get/set ?
   ip_enable_group_ifs 
   length ?
   value ? 1

If set to 1, the outgoing interface is selected based on the source
address of the incoming packet.

If there is no cached entry, multiple default routes work in a 
round robin fashion. The entries for each destination are
cached for 20 minutes (can be set by 'ip_ire_flush_interval').

More information on Interface Groups can be found in SUN InfoDoc 20726.
Information on how multiple default routes work is in SUN InfoDoc 17516.

Hope this helps.

Regards,

Thomas Kruel
Network Administrator,
Max-Born-Institute for Nonlinear Optics, Berlin

---
 
On 30 Jul 2004 at 10:35, James M Galvin wrote:

> I'm trying to setup a multi-homed host with three network interfaces.  I
> would like outbound traffic to share the three interfaces equally but
> I'm having trouble making that happen.  I'd also like to do this more or
> less statically.
>
> [...] 
> Thanks for any help,
> 
> Jim