From: Justin Menga (Justin.Menga@xxxxxxxxxxxxxxxxxx)
Date: Mon Jan 29 2001 - 06:26:56 GMT-3
Hi,
You can filter routes but you can lose reduncancy in your network - so you
rather assign the less preferable routes with a higher administrative
distance rather than actually blocking them from the route table. This way,
when the preferable route disappears, you have the less preferable route
available.
See Jeff Doyles Book for a good explanation...
Regards,
Justin Menga CCIE #6640 MCSE+I CCSE
WAN Specialist
Computerland New Zealand
PO Box 3631, Auckland
DDI: (+64) 9 360 4864 Mobile: (+64) 25 349 599
mailto: justin.menga@computerland.co.nz
-----Original Message-----
From: Piperw222@aol.com [mailto:Piperw222@aol.com]
Sent: Monday, January 29, 2001 3:04 PM
To: ccielab@groupstudy.com
Subject: CCIE BOOTCAMP LAB7 - ROUTING LOOPS
Hi everyone,
I have been working with lab 7 and I am trying to understand the logic
of what is going on with some of the configs - in preventing the routing
loops via the redistribution gong on in both R6 and R2. can anyone explain
to
me the logic of the administrative distance and access-lists in the
following
configs as well as how this prevents routing loops from occurring... In
addition why is it that you need to have rip version2 between r2 and r6 is
it
because of the requirement or is it needed for routing to work more
efficiently.
Thanks,
R6
router ospf 1
redistribute rip metric 100 subnets
network 10.100.1.6 0.0.0.0 area 0
network 10.6.1.1 0.0.0.0 area 6
distance 130
distance 110 0.0.0.0 255.255.255.255 1
!
router rip
timers basic 5 15 0 30
redistribute ospf 1 metric 2
passive-interface Ethernet0
passive-interface Serial0
network 10.0.0.0
distance 130
distance 120 10.65.1.2 0.0.0.0 2
!
no ip classless
no logging console
access-list 1 permit 10.3.0.0 0.0.255.255
access-list 1 permit 10.33.0.0 0.0.255.255
access-list 1 permit 10.101.0.0 0.0.255.255
access-list 1 permit 137.20.20.0 0.0.0.255
access-list 2 permit 10.51.0.0 0.0.255.255
access-list 2 permit 10.21.0.0 0.0.255.255
access-list 901 deny any any all any sap
access-list 901 deny any any all any rip
access-list 901 deny any any all any 457
access-list 901 permit any any all any all
!
R2
router ospf 1
redistribute rip metric 100 subnets
network 10.101.1.2 0.0.0.0 area 0
network 137.20.20.1 0.0.0.0 area 2
default-information originate metric 200 metric-type 1
distance 130
distance 110 0.0.0.0 255.255.255.255 1
!
router rip
version 2
timers basic 5 15 0 30
redistribute ospf 1 metric 2
passive-interface Ethernet0
passive-interface Serial0
network 10.0.0.0
distance 130
distance 120 10.21.1.2 0.0.0.0 2
!
no ip classless
ip route 0.0.0.0 0.0.0.0 137.20.20.2
no logging console
access-list 1 permit 10.33.0.0 0.0.255.255
access-list 1 permit 10.3.0.0 0.0.255.255
access-list 1 permit 10.6.0.0 0.0.255.255
access-list 1 permit 10.100.0.0 0.0.255.255
access-list 2 permit 10.51.0.0 0.0.255.255
access-list 2 permit 10.65.0.0 0.0.255.255
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