You're reading it correctly. The real problem isn't with router C. Using either of the methods I tried it learns a default route from B. The real problem is that as soon as I add a default-network command to router B (so that it originates a default to C) default routing breaks.
Others keep pointing out that having a loopback address as a default network creates a blackhole. In this case I'm using a dummy network that does not exist elsewhere so it won't create a black hole. In fact, when ip packet debugging is turned on the packets are unroutable. This makes no sense to me since a quad-zero default exists in the routing table. With ip classless nothing should be unroutable. Very weird. I must be missing something... You think this is weird, though, you ought to see the lab setup I'm using to test this. At the moment I have six routers running a combination of IS-IS, BGP, OSPF, and IGRP. :-) I'm a glutton for punishment! Regards, John On Sun, 4 Nov 2001 11:52:26 -0500, Chuck Larrieu wrote: | if I am not mistaken, the default network has to be "learned" via IGRP, and | cannot be a connected interface. If I am reading your outputs correctly, | your default network is a connected interface. | | am I misreading which router is the source of the pings? | | Chuck | | | ""John Neiberger"" wrote in message | [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... | > I posted this to the ccie list as well. I'm hoping someone has run across | > this before. | > | > 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 | > | > | > | > | > | > | > _______________________________________________________ | > Send a cool gift with your E-Card | > http://www.bluemountain.com/giftcenter/ | | | | _______________________________________________________ Send a cool gift with your E-Card http://www.bluemountain.com/giftcenter/ Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=25229&t=25216 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
