routing tables on two NICs for network monitoring

[Alexander Dalloz]

Am Do, den 22.01.2004 schrieb Shawn Iverson um 13:51:
> > From: Rick Stevens [mailto:rstevens at vitalstream.com]
> > Sent: Wednesday, January 21, 2004 9:03 PM
> > > 
> > > route add -net 10.0.0.0 netmask 255.0.0.0 gw 10.32.0.254 dev eth0
> > > route add -net 192.168.0.0 netmask 255.255.0.0 gw 
> > 10.32.0.254 dev eth0
> 
> Aren't these lines above ok?  If I don't specify 10.32.0.254 as the gateway,
> nothing will go beyond the 10.10.0.0/16 subnet.  I have many subnets with
> 10.x.0.0/16 addresses spanning several buildings and one 192.168.1.0/24
> subnet.
> 
> > > 
> > > /etc/sysconfig/network-scripts/route-eth0 is my guess to 
> > add the above to
> > > make the changes permanent
> > > 
> > > GATEWAY0=10.32.0.254
> > > NETMASK0=255.0.0.0
> > > ADDRESS0=10.0.0.0
> > > GATEWAY1=10.32.0.254
> > > NETMASK1=255.255.0.0
> > > ADDRESS1=192.168.0.0
> > 
> > GOD NO!  Bad dog!  Bad!  NEVER assign a host an IP address that's the
> > same as the network (your "ADDRESS0=10.0.0.0" and
> > "ADDRESS1=192.168.0.0" lines).  Also NEVER assign a host the 
> > IP address
> > that is the broadcast address for the net (where the host bit is all
> 
> I thought that I was specifying a network above, not a host.  Does that mean
> that the route-eth0 file only does routes to hosts?  I want to make the
> network routes persistent (ifdown/ifup/reboot all do not cause the routes to
> vanish).
> 
> > 
> > Put the default gateway in /etc/sysconfig/network:
> > 
> > 	GATEWAY=172.16.1.1
> > 
> > and remove it from any /etc/sysconfig/network-scripts/ifcfg-ethx file.
> > You should NEVER have more than one default route.  Each 
> > ifcfg-ethx file
> > should have the following lines at a minimum:
> > 
> > 	DEVICE=
> > 	BOOTPROTO=
> > 	IPADDR=
> > 	NETMASK=
> > 	ONBOOT=
> > 
> > The "NETWORK=" and "BROADCAST=" are optional.
> > 
> > You shouldn't need any routes at all for your internal 
> > network, provided
> > the IP addresses you're hitting are all on the 10.0.0.0/8 network (in
> > other words, all the internal stuff is on 10.x.y.z).  By 
> > default, you've
> > set eth0 to be on that network.  If you need to speak to 
> > 192.168.0.0/16,
> > then add a static route.  The command would be:
> > 
> > 	route add -net 192.168.0.0 netmask 255.255.0.0 device eth0
> 
> That's all good and well, but the network has many subnets beyond the
> 10.10.0.254 gateway spanning many buildings, i.e. 10.11.x.x/16 and
> 10.12.x.x/16 etc.  If I do this then no traffic will go beyond the local
> subnet.  Also, the route command does not make routing table changes
> persistent, AFAIK, and I have been advised not to use rc.local for network
> configurations because rc.local will not execute when ifdown/ifup are
> invoked or if the interface becomes unplugged.

Explanation for Redhat 9, but same for Fedora:

http://www.akadia.com/services/redhat_static_routes.html

Alexander


-- 
Alexander Dalloz | Enger, Germany
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