RE: tlug: PPP thanks

["Stephen J. Turnbull" <turnbull@example.com>]

>>>>> "Michael" == Michael Chiu <mchiu@example.com> writes:

    Michael> I discovered a new error with my PPP last night.. when I
    Michael> connect, it says something about not routing to
    Michael> eth0[0.0.0.0]

Do you have an ethernet card installed _and_ hooked to a net?  If not, 
when you do 

/sbin/ifconfig			# ifconfig probably lives in /sbin...

there should be no line ending in "eth0" (which is the first ethernet
interface (card) in the system).  If there is try

/sbin/ifconfig eth0 down

Even if you _do_ have a local ethernet set up already (you mentioned
IP masquerading), it's worth an experiment to shut the interface down.
To bring it back up, the simplest way is to reboot.  (It's not hard to
do directly, you just need to know how the route command works and
what data to feed it; I'd give you a recipe but I don't have the
data.)  Unless you're using NFS you won't miss the ethernet for a few
minutes.

    Michael> does anyone know what I should do?  do I need to set up
    Michael> something in my etc/hosts file so that I can force
    Michael> something into that address?

No.  That's not a address in the usual sense, it's a network.  (In
fact, it's the entire Internet.)  All manipulations of network
addresses (that you care about at this stage) can be carried out with
the `route' command.

    Michael> also, comparing my route -n with the other ones which
    Michael> were posted here yesterday, I realized that I don't have
    Michael> the 0.0.0.0 address listed in there...

That's OK at the moment; it doesn't interfere with pinging the other
end of your PPP link.

1.  Try `ping 127.0.0.1'.  If that doesn't work, either `ping' or your
whole networking subsystem (software, that address exists only in the
kernel's imagination, not in hardware anywhere) is fried.

2.  If that works, try `ping localhost'.  This is an alias in your
/etc/hosts file.  If it doesn't work, either your /etc/hosts or your
/etc/resolv.conf is hosed; post them both.  Either way, continue to
step 3 (/etc/hosts is optional as is name service at this stage).

3.  If that works, try `ping -c 3 165.76.23.253' (or whatever shows up
this time in the P-t-P slot of the output from `ifconfig ppp0').  If
it doesn't work, try `ping -r -c 3 165.76.23.253'.  The `-c 3' says
send three packets which takes 3 seconds; the `-r' says "ignore the
routing tables" (on my ping, anyway, there are different versions).
You could also try adding the `-v' (verbose) option, but I don't think
that should give you more than you're getting already.  If only the
`-r' version works, you might be getting "network unreachable" from
the no-`-r' version.

I don't know if this works as I expect for point-to-point networks.

4.  If either of those work, try `ping -c 3 165.76.21.201' (substitute
the `inet addr' from `ifconfig ppp0'.  This should not work (if pings
to IP addresses not yet mentioned don't work), and the `-r' version
should definitely not work (that address needs to be routed via
165.76.23.253, and `-r' does no routing by definition).

5.  If you are at this point unable to ping any IP address (except
perhaps your P-t-P partner) then do `route -n'.  For all routes
on the ppp0 interface do

route del <IP-address>

where the argument is the first IP address on the line.  Then do

route add -host 165.76.23.253 dev ppp0

(substituting the appropriate address of the P-t-P partner).  Try
pinging it again.  If you can't ping yet, yell "baka-yarou!", take a
few alka-seltzer, and go to the store and buy Windows.  :-(
Alternatively, lug your box to HBSC on Dec 13.  :-)

6.  If that ping worked, do

route add default gw 165.76.23.253

(which is actually an abbreviation for

route add -net 0.0.0.0 netmask 0.0.0.0 gw 165.76.23.253 dev ppp0)

and you should be able to ping any IP address in the world (that has
an active host attached :-).

After that you need to set up name service and the like.



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