From: Eric Taylor (etaylor10@tampabay.rr.com)
Date: Sun Mar 13 2005 - 00:56:23 GMT-3
Tim,
It looks like using the "ip unnumbered" for the IP address might be causing
a problem. I noticed how you only see 255.255.255.255 going to the loopback
interface in your debugs.
Now, about the directed broadcast and broadcast conversion....
In the testing that I've done, I noticed that a directed broadcast gets
converted to a broadcast address when it hits the local segment. The only
way that I've seen to change that is by using the "ip broadcast-address
54.8.7.255" command on the interface. Then you will see 54.8.7.255 being
broadcasted on that segment.
So for your example, that is the loopback interface which leads me to think
the unnumbered address is causing you some grief.
Let me know what you find out.
HTH,
Eric
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
ccie2be
Sent: Saturday, March 12, 2005 6:12 PM
To: Group Study
Subject: Can't ping bcast address
Hi guys,
I don't get this. Maybe someone can fill me in.
There are a couple of strange things happening.
Notice in the debug output below, when I ping the broadcast address, the
debug shows dest address as 255.255.255.255
not 54.8.7.255 which is the address I actually pinged. Also, notice that
ping's to 54.8.7.254 work fine.
So, I have 2 questions:
Why is the router changing the broadcast address I'm pinging?
And, why isn't the ping to the bcast address working?
Also, notice that the config does include the broadcast keyword which I so
often forget.
Here's the config:
interface Loopback0
ip address 54.8.7.6 255.255.255.0
!
interface ATM0/0
no ip address
no ip route-cache cef
no atm ilmi-keepalive
!
interface ATM0/0.208 point-to-point
pvc 0/208
broadcast
encapsulation aal5snap
protocol ppp Virtual-Template1
!
interface Virtual-Template1
ip unnumbered Loopback0
ppp chap hostname ROUTER6
ppp chap password 0 CISCO
R6#p 54.8.7.254
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 54.8.7.254, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms
R6#p 54.8.7.255
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 54.8.7.255, timeout is 2 seconds:
.....
*Feb 10 21:27:58.687: IP: s=54.8.7.6 (Loopback0), d=255.255.255.255, len
100, un
routable
*Feb 10 21:27:59.735: IP: s=54.8.7.254 (Virtual-Access1), d=224.0.0.10, len
60,
unroutable
*Feb 10 21:28:00.687: IP: s=54.8.7.6 (local), d=255.255.255.255 (Loopback0),
len
100, sending broad/multicast
*Feb 10 21:28:00.687: IP: s=54.8.7.6 (Loopback0), d=255.255.255.255, len
100, un
routable
*Feb 10 21:28:02.687: IP: s=54.8.7.6 (local), d=255.255.255.255 (Loopback0),
len
100, sending broad/multicast
*Feb 10 21:28:02.687: IP: s=54.8.7.6 (Loopback0), d=255.255.255.255, len
100, un
routable
*Feb 10 21:28:04.687: IP: s=54.8.7.6 (local), d=255.255.255.255 (Loopback0),
len
100, sending broad/multicast
*Feb 10 21:28:04.687: IP: s=54.8.7.6 (Loopback0), d=255.255.255.255, len
100, un
routable
TIA, Tim
This archive was generated by hypermail 2.1.4 : Sun Apr 03 2005 - 17:56:45 GMT-3