[KLUG Members] Re: IP Routing and other issues... -- no, you can't ping without a route

[Bryan J. Smith]

Quoting Tahnesha Pinckney <tep@hanify.com>:
> Well, unfortunately, for some reason, I seem to do things the hard way.
> What I mean is, the windows machines all have a 198.200.194.*. naming
> convention and the linux machines have a 192.100.115.*. naming
> convention.  Since both use the same subnet mask, theoretically, I
> should be able to ping between the two.  But, that doesn't seem to be
> the case.

No you shouldn't be able to ping between the two at all.  The "Netmask" is just
that, a "network mask."

Simple boolean logic here ([AND] = boolean AND operation):

  Src IP [AND] Src Mask == Dest IP [AND] Dest Mask -> Same Net
  Src IP [AND] Src Mask != Dest IP [AND] Dest Mask -> Not Same Net

The first doesn't need to be routed.  The second does.

(/24 = 255.255.255.0)

  198.200.194.* [AND] /24 ?? 192.100.115.* [AND] /24
          192.100.194.0 != 192.100.115.0

Not local.  You need a route.  Doesn't matter if they are using the same switch
or wire, you need a route.

Or the simple fix is to just put them all on the same subnet.  Of course, that
doesn't help you if you still try to ping via name (as I posted about earlier).

-- 
Bryan J. Smith, E.I.               Contact Info:  http://thebs.org
[ http://thebs.org/files/resume/BryanJonSmith_certifications.pdf ]
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