[Discuss] Linux routing question

[Rajiv Khaneja]

If I'm not mistaken, I think he is more interested in monitoring services on
the remote servers (i.e. ping check;  or a check to see if the http server
is up etc)

Under your current routing setup Steven is correct. Your gateway (
192.168.10.254) would need to know how to reach the other networks...

However, if all of your servers are setup on the same side of a router (e.g.
192.168.0.x and 192.168.n.x etc are plugged into the same switch or groups
of switches with no router involved)  then you simply need to change your
netmask to reach them.  Basically a netmask is used to identify the local
portion of a local area network.  What you need to do is tell your servers
that everything in the range 192.168.0.0 to 192.168.254.254 is local and
that packets destined for any address in that range need not be directed to
the gateway router.

A netmask of 255.255.0.0 will enable your server to communicate directly
with every device in the range 192.168.0.0 to 192.168.254.254 -- however,
keep in mind, that the netmasks on each of the servers you are monitoring
would also need the corresponding change in order for the monitor to receive
a reply from them. Otherwise their replies will be sent to their gateways
and your monitoring server will perpetually think they are down!

Now, if I am completely wrong in my assumption that all your servers are
connect to the same switch -- please reply with a description of your
network topology (i.e. what is plugged in where and connected to whom)  and
I'll try and help you...

Hope that helps...

Cheers,
Rajiv







On 4/16/08, Noel Burton-Krahn <noel at burton-krahn.com> wrote:
>
> It sound like you want to make a network sniffer.  If that's the case
> you don't need any routes at all, you just need to be attached to the
> cable where the traffic is flowing through:
>
> subnet1  ---------------- sniffer ----------- router --------------
> internet
> subnet2
>
> tcpdump in promiscuous mode will read all traffic on a NIC.
>
> Your route settings don't affect receiving packets, only what
> interface a packet gets sent out on.
>
>
> ~Noel
>
>
>
>
> On Wed, Apr 16, 2008 at 3:50 PM, Johnny Stork <lists at openenterprise.ca>
> wrote:
>
> > I have a client for whom I am setting up some monitoring solutions and
> they
> > run various subnets and so in order for the monitoring machine to reach
> and
> > monitor devices on the other subnets, I beleive I need additional
> routes?
> > For instance, the monitoring server has the ip 192.168.10.71, but it
> will
> > need to monitor devices on 192.168.0.x and 192.168.254.x etc. How and
> where
> > would I need to add any additional routes? Below is the current routing
> > table:
> >
> >
> >
> >  root at dev:/etc/rc.d/init.d# route
> >  Kernel IP routing table
> >  Destination     Gateway         Genmask         Flags Metric Ref    Use
> > Iface
> >  192.168.10.0    *               255.255.255.0   U     0      0        0
> > eth0
> >  169.254.0.0     *               255.255.0.0     U     0      0        0
> > eth0
> >  default         192.168.10.254  0.0.0.0         UG    0      0        0
> > eth0
> >  _______________________________________________
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> >
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