Interesting... thanks for the explanation Chuck. Hal
> -----Original Message----- > From: Chuck Larrieu [mailto:[EMAIL PROTECTED]] > Sent: Monday, December 10, 2001 12:32 AM > To: [EMAIL PROTECTED] > Subject: RE: RIP routing (2 router lab) newbie [7:28327] > > > I spent a bit more time looking into this one than it may be > worth. But my > look did reinforce some points made in this thread and in > another thread > started by John Neiberger and researched so ably by Nigel > Taylor - that is, > the nature and behaviour of secondary addresses. > > Sorry I am unable to document everything I did here. It would take me > writing a Jeff Doyle type chapter on RIP to get it all out > and explained, > with screen shots etc. > > To put things in terms of how I observed them: > > In the case of RIP, by default, advertisements are sent out > an interface > using the primary address of that interface as the source address. > > if another router on the segment is using and address that is > not on the > same subnet as the primary, that router will see messages like this: > > 01:46:25: RIP: ignored v1 update from bad source 172.29.101.1 > on TokenRing0 > 01:46:30: RIP: ignored v1 update from bad source 172.29.101.2 > on TokenRing0 > 01:46:35: RIP: sending v1 update to 255.255.255.255 via TokenRing0 > (172.29.103.7) > > 103.1 was secondary address on my R1, 103.7 the address of my > R3 You can see > the error referring to 101.1 and 102.1 ( the address of > another router on > the segment ) > > I threw in a no ip split-horizon command on the interface of > my R1, and lo > and behold, it started sourcing rip packets from 101.1, 102.1 > and 103.1 and > all my RIP routes propagated > > from CCO: > > Note If any router on a network segment uses a secondary > address, all > other routers on that same segment must also use a secondary > address from > the same network or subnet. > > > some of us already commented about issues with secondary > routes among the > various routing protocols. the point being that using > secondary addresses > can be tricky, and is probably not a good idea for newbies > just trying to > learn the basics. if you want to see how things work, use > loopbacks. with > secondary addresses, it is to easy to end up fighting with > some complex > issues beyond a beginner's understanding. in fact, there are > some advanced > students who find this topic complex and mysterious. > > best wishes. > > Chuck > > BTW, one of the implications of this study was a walk down > memory lance. A > guy named Bob Vance who used to hang here a lot and who was > the progenitor > of a number of interesting discussions once postulated that > all stations on > a segment will see the all F's broadcast, even if their layer three > addresses are different ( i.e. seconday's ) the output above > is something of > a proof of that supposition. The router saw the RIP packets with the > destination address of 255.255.255.255 ( MAC FFFF.FFFF.FFFF > ), processed the > packet, saw the source address as being on a different subnet > ( even though > on the same segment ) and rejected the packet. Interesting. > Especially in > that all subnets were part of the same Class B network. > > > > > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of > Logan, Harold > Sent: Friday, December 07, 2001 6:21 AM > To: [EMAIL PROTECTED] > Subject: RE: RIP routing (2 router lab) newbie [7:28327] > > > It looks like Anil wants to get RIP to advertise the 193.9.200.0 > network. A secondary address may work on one of the interfaces, but it > would need to be on a different subnet. Notice from the > config, he gave > the secondary address the same IP as the primary addy. No > matter what he > does with the 193.9.200.0 network, those two routers will > always show it > as being "Directly Connected" instead of learned through RIP; > DC routes > have an administrative distance of 0, whereas RIP has an AD of 120. In > the routing table, the router is only going o show the route with the > best (lowest) distance. He could add a loopback on a > different subnet on > one of the routers, then add network statements for that subnet, and > then he would see that network learned via RIP on the opposite router. > Likewise Anil, if you had a 3rd router connecting to one of your two > routers by the BRI port, that 3rd router would learn of the > 193.9.200.0 > network through RIP. (Granted, RIP wouldn't be your ideal routing > protocol for an ISDN line, but that's going a little bit > deeper than you > need to for now) > > Try these configs, then look at your routing tables: > > > hostname rustya > > ! > > enable secret 5 $1$Ws8V$mRIwI97bc/Iv7PAEKFBVo1 > > ! > > interface Loopback0 > > ip address 200.10.10.1 255.255.255.0 > > ! > > interface Ethernet0 > > ip address 192.9.200.1 255.255.255.0 > > ! > > interface BRI0 > > no ip address > > shutdown > > ! > > router rip > > network 193.9.200.0 > > network 200.10.10.0 > > ! > > no ip classless > > ! > > line con 0 > > line vty 0 4 > > password cisco > > login > > ! > > end > > > > hostname rustyb > > ! > > enable secret 5 $1$JycL$W4sNa8kuL2.tppX2IYQJU/ > > ! > > interface Loopback0 > > ip address 201.10.10.1 255.255.255.0 > > ! > > interface Ethernet0 > > ip address 192.9.200.2 255.255.255.0 > > ! > > interface BRI0 > > no ip address > > shutdown > > ! > > router rip > > network 196.9.200.0 > > network 201.10.10.0 > > ! > > no ip classless > > ! > > line con 0 > > line vty 0 4 > > password cisco > > login > > ! > > end > > hth, > Hal > > > > -----Original Message----- > > From: Kane, Christopher A. [mailto:[EMAIL PROTECTED]] > > Sent: Thursday, December 06, 2001 9:26 PM > > To: [EMAIL PROTECTED] > > Subject: RE: RIP routing (2 router lab) newbie [7:28327] > > > > > > I'm not sure if RIP is the same as OSPF, but if so, you > must have OSPF > > running on the interface via the Primary address in order > to have the > > Secondary address also participate in OSPF. Did you try > > adding your Primary > > address (network statement) to RIP also? > > > > Chris > > > > > > > > -----Original Message----- > > From: Chuck Larrieu > > To: [EMAIL PROTECTED] > > Sent: 12/6/01 5:45 PM > > Subject: RE: RIP routing (2 router lab) newbie [7:28327] > > > > try using loopbacks instead of secondaries. Are your > > secondary addresses > > part of the RIP process via network statements? same subnet > > boundary as > > the > > primary address? > > > > Chuck > > > > -----Original Message----- > > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED]]On Behalf Of > > anil > > Sent: Thursday, December 06, 2001 2:03 PM > > To: [EMAIL PROTECTED] > > Subject: RIP routing (2 router lab) newbie [7:28327] > > > > > > 2 C1603's connected to a hub. > > It should be simple but I cannot see why RIP does not > > update the routing tables (in either direction). > > I added secondary addresses to both routers e0, and want RIP to send > > these > > routes. > > > > Any comments/suggestions welcome. > > Many thanks > > -Anil > > > > > > --------- > > rustya#sh ip route > > > > Gateway of last resort is not set > > C 193.9.200.0/24 is directly connected, Ethernet0 > > C 192.9.200.0/24 is directly connected, Ethernet0 > > rustya# > > ------------------------------ > > hostname rustya > > ! > > enable secret 5 $1$Ws8V$mRIwI97bc/Iv7PAEKFBVo1 > > ! > > ! > > interface Ethernet0 > > ip address 193.9.200.1 255.255.255.0 secondary > > ip address 192.9.200.1 255.255.255.0 > > ! > > interface BRI0 > > no ip address > > shutdown > > ! > > router rip > > network 193.9.200.0 > > ! > > no ip classless > > ! > > line con 0 > > line vty 0 4 > > password cisco > > login > > ! > > end > > > > > > > > -------------------------------- > > rustyb#sh ip route > > > > Gateway of last resort is not set > > > > C 192.9.200.0/24 is directly connected, Ethernet0 > > C 196.9.200.0/24 is directly connected, Ethernet0 > > rustyb# > > -------------------------------- > > hostname rustyb > > ! > > enable secret 5 $1$JycL$W4sNa8kuL2.tppX2IYQJU/ > > ! > > ! > > interface Ethernet0 > > ip address 196.9.200.1 255.255.255.0 secondary > > ip address 192.9.200.2 255.255.255.0 > > ! > > interface BRI0 > > no ip address > > shutdown > > ! > > router rip > > network 196.9.200.0 > > ! > > no ip classless > > ! > > line con 0 > > line vty 0 4 > > password cisco > > login > > ! > > end Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=28698&t=28327 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
