[ale] home networking difficulties

[Joseph A. Knapka]

Geoffrey wrote:
> 
> You might try networking the Linux box to itself.  That is, set the two
> nics to be in the same subnet and connect them both to the hub.  This
> way you might reduce the possible issues substantially.  From that
> point, you could verify the cables/cards are functional.

Does that work? I'm under the impression that the Linux network
layer, confronted with this situation, will just say, "Oh,
both IPs point to this machine, so there's no reason to
actually touch any hardware."

>  Is it
> possible, the win box and linux box are trying to talk different speeds?
>   (one 10 the other 100).  I'm grasping now (or gasping??).
 
Nope. ARP works in both directions, therefore data can move
successfully across the cable, and be processed by the
software on both machines. (Unless arp is implemented in
the NIC hardware sometimes? I just thought of that...)

> Further comments below.
> 
> Andrew Grimmke wrote:
> 
> > 1.  The hardware is working, at least to some degree.
> > arp apprear to work fine (according to the tcpdump and
> > windump outputs), it's icmp that is not working.
> 
> I don't know that we can say this definitely just yet.  I would have
> expected that once you shutdown the firewalls on both machines that you
> should have been able to either telnet or ping from one to the other in
> at least one direction.
>
> >
> > 2. I have sent and recieved icmp packets from the linux
> > box in the past.  So, although I initially thought that
> > maybe linux was blocking ping responses, I am thinking
> > that's a long shot now.
> 
> Agreed, since you did turn off the firewall and make the same attempt.
> 
> >
> > 3. I have had trouble with icmp on the windows box
> > before.  I remembered this recently.  When I first got
> > broadband (and was only running windows) I tried to get
> > a friend to ping me with no luck.  I can ping myself
> > (192.168.1.2) internally, however.
> 
> But pinging yourself more then likely goes the local loop (127.0.0.1) so
> it never touches the nic, wire, or that subnet.

Yep. Or actually, it doesn't go to the local loop -
that's a distinct interface - but it certainly doesn't
touch hardware.
 
> >
> > 4. The Windows firewall is off.  Although it is still
> > installed, I have removed it from the startup routine.
> 
> I guess you could uninstall it to insure they're not trying to 'protect
> you from yourself' which seems to be a common thread through windows
> software.

Just what I was thinking. I've had experiences
before where, for example, a service would magically
be changed back to "Automatic" startup, after I'd
gone in and explicitly changed it to "Manual".
Yes, I know, Windows is smarter than me...
 
 
> >
> > I am starting to think this is a Windows problem.  Like
> > some kind of "stealth mode" where it ignores icmp
> > packets.  I could find nothing about this on the net,
> > unfortunately.  And of course this is just a hypothesis.
> 
> See note above. :)
> 
> --
> Until later: Geoffrey           esoteric at 3times25.net
> 
> I didn't have to buy my radio from a specific company to listen
> to FM, why doesn't that apply to the Internet (anymore...)?
> 
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-- Joe
  "I'd rather chew my leg off than maintain Java code, which
   sucks, 'cause I have a lot of Java code to maintain and
   the leg surgery is starting to get expensive." - Me

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