Re: Network address Problem

From: Josh Duffek (jduffek@cisco.com)
Date: Sun Jan 27 2002 - 14:56:57 EST


tom and mike: ip classless?

tejal:

where are you trying to ping from? can you ping from the router? if so
then you have a default gateway problem(host routing problem). if not then
you have a routing problem(router routing problem).

sh ip route would be good, along with the requested network diagram. here
is what i can guess it looks like, as basic as I can make it:
---10.10.10.0/27---<router>---10.10.10.32/27---
(i could assume there is a second router involved, in between the
subnets...but from a support perspective i don't like to assume anything)

i would do this:

sh ip access
!find an unused acl number, lets say 150
config t
access-list 150 permit icmp any host 10.10.10.30
!could be an address of any host that has a working ip stack in that subnet
access-list 150 permit icmp host 10.10.10.30 any
end
debug ip pack 150
debug arp
term mon !or whatever
ping 10.10.10.30

this should show what is happening to the packet. if you are pinging
through the router you may have to turn of fast switching(no ip route-cache)
on the incoming interface to get the packet to show up in debug. you may
also need to do some packet sniffing on the lan but i doubt your problem
will be that hard to isolate.

basically, you need to follow the packet from the host-to-destination and
see where it is getting lost, then correct that problem. the router should
receive the packet, check to see if he has a route for it, if so then he
forwards it...if not the packet is dropped...

joshd

----- Original Message -----
From: "Tom Scott" <telecomtom@dacor.net>
To: "Michael K. Smith" <mike@wackypackets.com>
Cc: "Tejal Shah" <tejal.shah@surat.iqara.net>; <cisco-nsp@puck.nether.net>
Sent: Sunday, January 27, 2002 2:26 AM
Subject: Re: Network address Problem

> Mike, that's what I was thinking too. Tejal, can you draw a diagram with
> ascii art or attach a Visio/Dia with a jpg or gif format? And possibly,
what
> do you mean when you say "if i ping from my network"? Are there three
> networks/subnetworks you're dealing with (your network, ? Anhother thing
that
> might help is the output of the "sho ip route" command on the 2 (3?)
routers,
> and the IP addr and SM of the workstation/PC you're pinging from.
>
> -- TT
>
> "Michael K. Smith" wrote:
>
> > Hello:
> >
> > Well, I can only guess it is because you need the following command
turned
> > on.
> >
> > ip subnet-zero
> >
> > Mike
> >
> > On Sat, 26 Jan 2002, Tejal Shah wrote:
> >
> > > Hi all,
> > >
> > >
> > > I have subnet my one /24 ip block in 2 /27 network.
> > > Example:- 10.10.10.0/24 255.255.255.0 is original ip
> > > block.
> > >
> > > I have subnetted it in 2 /27 ip blco i.e.
> > > >>>10.10.10.0/27 255.255.255.224 &
> > > >>>10.10.10.32/27 255.255.255.224
> > >
> > > IF i ping 10.10.10.0 and 10.10.10.31 from my network i m
> > > not able to ping it but if i ping 10.10.10.32 ang
> > > 10.10.10.63 i am able to ping.
> > >
> > > Can anybody tell me why it is happening.
> > >
> > > Tejal
> > >
> > >
> > > Go To http://www.iqara.net
> > >
> > >



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