RE: ping 172.16.255.255

From: Jason Luo (luoz@xxxxxxxxx)
Date: Wed Sep 05 2001 - 12:45:49 GMT-3


   
hi, group and Lionel

thanks, Lionel.

but i have the following topology to test the result.

     172.16.x.x
                                _____
____
                                     |
|
                      1.1/24*(R1)*3.2/24-------------3.1/24*(R3)*2.2/24
                           |
/
                           |
/
                           |
/
                     1.2/24*(R2)*2.1/24 ---------------------------- /
                                     |
                                   -----

All 3 routers are connected with serial line(back-to-back).
No dynamic routing protocols configured and each router has 2 "C" routes.
I used the "debug ip icmp" on every router.
and I lauched the "ping 172.16.255.255" on each router.
reply only can be seen on one of the 2 directly connected lines.
If i ping with the source address of the ethernet interface(up-up), the is
no any response.

What is wrong with me??
thanks so much again.
Good luck

jason

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Lionel Gourvitch
Sent: 2001?9?5? 17:20
To: Jason Luo
Cc: ccielab@groupstudy.com
Subject: Re: ping 172.16.255.255

if you ping 172.16.255.255 and all your router have "ip subnet-zero"
configured then all the devices on the "last subnet"( that contains the
broadcast address 172.16.255.255) of 172.16.0.0 will do icmp reply. if "
ip subnet-zero" is not configured then all the devices on 172.16.0.0 will
do icmp reply.

Hope it helps

Lionel

At 04:40 PM 9/5/2001 +0800, Jason Luo wrote:
>Hi, group
>
>I have a question about the directed broadcast.
>There is a network using various sub-network from the 172.16.0.0.
>The length of subnet mask is various. (24 for lan and 30 for p-t-p)
>Use "ping 172.16.255.255", what will happen??
>Use "debug ip icmp" on every router, what can be seen?
>Which switches should be opened or closed??
>
>Thanks alot!!!
>
>Jason
>**Please read:http://www.groupstudy.com/list/posting.html
**Please read:http://www.groupstudy.com/list/posting.html
**Please read:http://www.groupstudy.com/list/posting.html



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