From: John Neiberger (neiby@xxxxxxxxxx)
Date: Sun Nov 04 2001 - 03:16:17 GMT-3
I'll start with the original scenario that worked so I can show you where I
began before I show you what I'm trying to accomplish now. There are three
relevant routers here:
A----(ospf)----B----(rip)-----C
A originates a default route to B and I use default-information originate in
the RIP config to pass 0.0.0.0/0 to C. This works well. Then I took RIP
away and tried this with IGRP and ip default-network.
This took some tweaking before I could get B to originate default route to
C with IGRP. Is it just me or did Cisco seem to make this very
user-unfriendly?? Unbelievable. This is *so* easy with other protocols.
Anyway...
In the first scenario, B has a single gateway of last resort: 0.0.0.0/0 via
router A. Beautiful. In the second scenario I end up with two candidate
GOLRs but neither is picked and routing breaks!
This makes *zero* sense to me. If ip classless is configured and still
have 0.0.0.0/0 in my routing table then B should route all packets with
unknown destinations to A, right?? Well, it's not working and I can
consistently recreate it.
If I remove the ip default-network statement routing works but then C has no
default route.
What could be wrong here? For grins, I'll paste in some command output to
show you what I mean. R4 is "Router B" in the above scenario.
Gateway of last resort is 152.1.3.2 to network 0.0.0.0
152.1.0.0/16 is variably subnetted, 2 subnets, 2 masks
O IA 152.1.1.0/25 [110/74] via 152.1.3.2, 05:19:53, Serial0
C 152.1.3.0/30 is directly connected, Serial0
130.1.0.0/16 is variably subnetted, 9 subnets, 2 masks
I 130.1.3.0/24 [100/1188] via 130.1.4.2, 00:00:28, TokenRing0
I 130.1.2.0/24 [100/1188] via 130.1.4.2, 00:00:28, TokenRing0
I 130.1.1.0/24 [100/1188] via 130.1.4.2, 00:00:28, TokenRing0
O 130.1.0.0/22 is a summary, 05:19:54, Null0
I 130.1.7.0/24 [100/1188] via 130.1.4.2, 00:00:29, TokenRing0
I 130.1.6.0/24 [100/1188] via 130.1.4.2, 00:00:29, TokenRing0
I 130.1.5.0/24 [100/1188] via 130.1.4.2, 00:00:29, TokenRing0
O 130.1.4.0/22 is a summary, 05:19:54, Null0
C 130.1.4.0/24 is directly connected, TokenRing0
C 30.0.0.0/8 is directly connected, Loopback1
O*N2 0.0.0.0/0 [110/1] via 152.1.3.2, 05:19:56, Serial0
R4#ping 20.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 20.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 24/28/40 ms
R4#
After I add ip default-network 30.0.0.0:
Gateway of last resort is not set
152.1.0.0/16 is variably subnetted, 2 subnets, 2 masks
O IA 152.1.1.0/25 [110/74] via 152.1.3.2, 05:21:19, Serial0
C 152.1.3.0/30 is directly connected, Serial0
130.1.0.0/16 is variably subnetted, 9 subnets, 2 masks
I 130.1.3.0/24 [100/1188] via 130.1.4.2, 00:00:32, TokenRing0
I 130.1.2.0/24 [100/1188] via 130.1.4.2, 00:00:32, TokenRing0
I 130.1.1.0/24 [100/1188] via 130.1.4.2, 00:00:32, TokenRing0
O 130.1.0.0/22 is a summary, 05:21:19, Null0
I 130.1.7.0/24 [100/1188] via 130.1.4.2, 00:00:34, TokenRing0
I 130.1.6.0/24 [100/1188] via 130.1.4.2, 00:00:34, TokenRing0
I 130.1.5.0/24 [100/1188] via 130.1.4.2, 00:00:34, TokenRing0
O 130.1.4.0/22 is a summary, 05:21:20, Null0
C 130.1.4.0/24 is directly connected, TokenRing0
C* 30.0.0.0/8 is directly connected, Loopback1
O*N2 0.0.0.0/0 [110/1] via 152.1.3.2, 05:21:22, Serial0
R4#
R4#ping 20.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 20.1.1.1, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)
R4#
Any help would be appreciated. I'm about to swear off using IGRP and EIGRP
for the rest of my life just on principle. :-)
Thanks,
John
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