From: Cheung, Tom [JJMI-AR] (TCHEUNG@xxxxxxxxxxxxx)
Date: Thu Oct 12 2000 - 17:17:30 GMT-3
Title: FW: routing problem
But I'm not allow to use static routes in this exercise. I'm not sure
if default-network will be considered static route?
-----Original Message-----
From: Aaron K. Dixon [mailto:adixon@houston.omnes.slb.com]
Sent: Thursday, October 12, 2000 3:13 PM
To: Cheung, Tom [JJMI-AR]; ccielab@groupstudy.com
Subject: RE: routing problem
If you've summarized the routes to 172.17.59.0/26 then it won't know
about subnets above 192 due to your summary mask. I'm not sure what
you mean by finding the 182.17.59.0 subnet. I don't see that in your
table. You could use a default network on the IGRP router to allow it
to route to the next hop or send an additional summary route to the
172.17.59.192/26.
Regards,
Aaron K. Dixon
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Cheung, Tom [JJMI-AR]
Sent: Thursday, October 12, 2000 2:48 PM
To: 'ccielab@groupstudy.com'
Subject: FW: routing problem
All,
I have a general routing question. Here's the scenario:
serial serial
r5 ---------------------- R1 ------------------> frame
cloud
172.17.59.64/26 (IGRP) 172.17.59.x (OSPF, VLSM)
On OSPF side 172.17.59.x is variable subnetted into /28, /29 and
/30.
I injected the OSPF routes into IGRP by "summary-address
172.17.59.0 255.255.255.192"
From R5, I'm able to ping 172.17.59.5, 59.9, 59.17 etc. but was
unable to ping 59.193. It is "unroutable".
My explanation to why 192.17.59.193 is "not routable" is that R5
knows only 172.17.59.0/26 and 172.16.59.64/26. 192.17.59.192 is
not a 192.17.59.0 subnet. Therefore R5 drops packets for
192.17.59.193. But then, shouldn't "ip classless" force the router
to do longest match and find 182.17.59.0 for 59.193?
R5's show ip route, debug IP packet output during the ping fail are
attached for your reference.
[r5#
r5#sh ip ro
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B
- BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter
area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type
2
E1 - OSPF external type 1, E2 - OSPF external type 2, E -
EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * -
candidate default
U - per-user static route, o - ODR
Gateway of last resort is not set
172.17.0.0/26 is subnetted, 2 subnets
I 172.17.59.0 [100/159250] via 172.17.59.65, 00:00:17,
Serial0
C 172.17.59.64 is directly connected, Serial0
10.0.0.0/24 is subnetted, 1 subnets
C 10.1.2.0 is directly connected, Ethernet0
r5#
r5#
r5#deb ip packet
IP packet debugging is on
r5#ping 172.17.59.193
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.17.59.193, timeout is 2
seconds:
00:11:20: IP: s=172.17.59.66 (local), d=172.17.59.193, len 100,
unroutable.
00:11:21: IP: s=10.1.2.1 (local), d=255.255.255.255 (Ethernet0),
len 52, sending
broad/multicast
00:11:22: IP: s=172.17.59.66 (local), d=172.17.59.193, len 100,
unroutable.
00:11:24: IP: s=172.17.59.66 (local), d=172.17.59.193, len 100,
unroutable.
00:11:26: IP: s=172.17.59.66 (local), d=172.17.59.193, len 100,
unroutable.
00:11:28: IP: s=172.17.59.66 (local), d=172.17.59.193, len 100,
unroutable.
Success rate is 0 percent (0/5)
Tom
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