From: Andy Mrozek (AndyMrozek@yahoo.com)
Date: Sun Aug 22 2004 - 19:43:11 GMT-3
When going through this great book , I thought the Rip with neighbor /
passive interface was cool solution ...... So I tried it and was debugging ,
and when setting up what they had for a solution ... and doing a debug ip
rip ....... r3 will still show sending update to 224.0.0.9 ??? I also put
a sniffer on this same vlan/broadcast domain and sure enough I still see
broadcasts to the 224.0.0.9 group .... Has anyone else seen this ?? Here is
output from both config methods ... Both neighbor/passive interface and nat
method....... I hope I did something wrong and nat is actually unicasting ,
as that is cool way to take loud traffic and tune it down.......
ROUTER 3 SHOWING CISCO PRESS CCIE RS LAB PRACTICE LAB 1 PROBLEM STATEMENT
STATING NOT TO USE NEIGHBOR METHOD TO UNICAST TO A GIVEN NEIGHBOR BUT TO USE
NAT.
* This configuration is from the solution of lab 1 ... I still see r3
sending
rip updates to a multicast address ?? And a sniffer on this broadcast domain
also see's this ? Both examples are running ios 12.2(15)T code ?? Is there
an
order of operations issue here and debugging is seening it afterwords ?? If
so
why would a sniffer see multicast traffic , after this nat solution is
configured ???...
interface Loopback0
ip address 60.60.60.1 255.255.255.0
!
interface Ethernet0
ip address 172.16.0.2 255.255.0.0
ip nat outside
!
interface Ethernet1
no ip address
shutdown
!
interface Serial0
no ip address
shutdown
no fair-queue
!
interface Serial1
no ip address
shutdown
!
router rip
version 2
passive-interface default
no passive-interface Ethernet0
offset-list 1 out 14 Ethernet0
network 60.0.0.0
network 172.16.0.0
no auto-summary
!
ip nat outside source static udp 172.16.0.1 520 224.0.0.9 520 extendable
ip http server
ip classless
!
!
access-list 1 permit 60.60.60.0 0.0.0.255 log
!
r3#debug ip rip
*Mar 1 03:15:01.279: RIP: sending request on Ethernet0 to 224.0.0.9
*Mar 1 03:15:03.227: RIP: sending v2 flash update to 224.0.0.9 via
Ethernet0
(172.16.0.2)*Mar 1 03:15:03.231: RIP: build flash update entries
*Mar 1 03:15:03.231: 60.60.60.0/24 via 0.0.0.0, metric 15, tag 0
*Mar 1 03:15:23.623: RIP: received v2 update from 172.16.0.1 on Ethernet0
*Mar 1 03:15:23.627: 10.1.1.0/28 via 0.0.0.0 in 2 hops
*Mar 1 03:15:23.635: 10.4.4.0/29 via 0.0.0.0 in 3 hops
*Mar 1 03:15:23.639: 10.40.40.0/28 via 0.0.0.0 in 3 hops
*Mar 1 03:15:23.647: 10.80.80.0/24 via 0.0.0.0 in 2 hops
*Mar 1 03:15:23.651: 10.90.90.0/28 via 0.0.0.0 in 1 hops
*Mar 1 03:15:23.655: 10.100.100.0/28 via 0.0.0.0 in 2 hops
*Mar 1 03:15:25.635: RIP: sending v2 flash update to 224.0.0.9 via
Ethernet0
(172.16.0.2)*Mar 1 03:15:25.639: RIP: build flash update entries -
suppressing
null update*Mar 1 03:15:28.555: RIP: sending v2 update to 224.0.0.9 via
Ethernet0 (172.16.0.2)*Mar 1 03:15:28.559: RIP: build update entries
*Mar 1 03:15:28.563: 60.60.60.0/24 via 0.0.0.0, metric 15, tag 0
ROUTER 3 SHOWING TYPICAL WAY TO UNICAST RIP UPDATES TO A NEIGHBOR:
*debug output changes and shows when a neighbor is defined that instead of
sending to 224.0.0.9 it sends to 172.16.0.1 the ip in the neighbor
statement.
* We know typically when not using passive interface / neighbor statement a
rip
enabled router will send to 224.0.0.9 , and you can see this with a debug ip
rip
* If you want to unicast to a neighbor for security reasons or what not rip
allows you to passive-interface / neighbor statement to change the sending
rip
updates to 224.0.0.9 to the neighbor you specify and this can be seen with a
debug ip rip as seen below...
* So this common config below gives proof that rip is sending direct unicast
to
172.16.0.1 , I also had a sniffer on this broadcast domain , and did not see
the
rip broadcast come over which on a switch normally you do
r3#
hostname r3
!
boot-start-marker
boot-end-marker
!
!
username cisco privilege 15 password 0 cisco
no aaa new-model
ip subnet-zero
!
!
!
!
interface Loopback0
ip address 60.60.60.1 255.255.255.0
!
interface Ethernet0
ip address 172.16.0.2 255.255.0.0
!
interface Ethernet1
no ip address
shutdown
!
interface Serial0
no ip address
shutdown
no fair-queue
!
interface Serial1
no ip address
shutdown
!
router rip
version 2
passive-interface default
offset-list 1 out 14 Ethernet0
network 60.0.0.0
network 172.16.0.0
neighbor 172.16.0.1
no auto-summary
!
ip http server
ip classless
!
!
access-list 1 permit 60.60.60.0 0.0.0.255 log
r3#debug ip rip
RIP protocol debugging is on
r3#
*Mar 1 03:01:49.035: RIP: sending v2 update to 172.16.0.1 via Ethernet0
(172.16.0.2)*Mar 1 03:01:49.039: RIP: build update entries
*Mar 1 03:01:49.043: 60.60.60.0/24 via 0.0.0.0, metric 15, tag 0
*Mar 1 03:02:12.147: RIP: received v2 update from 172.16.0.1 on Ethernet0
*Mar 1 03:02:12.147: 10.1.1.0/28 via 0.0.0.0 in 2 hops
*Mar 1 03:02:12.151: 10.4.4.0/29 via 0.0.0.0 in 3 hops
*Mar 1 03:02:12.155: 10.40.40.0/28 via 0.0.0.0 in 3 hops
*Mar 1 03:02:12.159: 10.80.80.0/24 via 0.0.0.0 in 2 hops
*Mar 1 03:02:12.163: 10.90.90.0/28 via 0.0.0.0 in 1 hops
*Mar 1 03:02:12.167: 10.100.100.0/28 via 0.0.0.0 in 2 hops
*Mar 1 03:02:18.691: RIP: sending v2 update to 172.16.0.1 via Ethernet0
(172.16.0.2)*Mar 1 03:02:18.695: RIP: build update entries
*Mar 1 03:02:18.699: 60.60.60.0/24 via 0.0.0.0, metric 15, tag 0
This archive was generated by hypermail 2.1.4 : Fri Sep 03 2004 - 07:02:47 GMT-3