Re: preferring OSPF inter-area compared to intra-area

WOW....
First of all what I wrote is very applicable to the question that ccie99999
had in this post. Because he was complaining that it does not work. The
following is his post:
"*What I was complaining is that route-map matching ip next-hop or matching*
*
ip route-source is not working when applied with a distribute list inbound
to ospf.
**Strange I don't find any official reference on this scenario.*"
Did i miss something?

What are you referring to? Please be more specific.
These are NOT labs from my book, people that have my books will tell you
that these labs are NOT from my book. I just took my time to respond with
the configuration that clearly shows that the options work correctly.
Besides even if I post something from my book, so what? Are you the
moderator? Why don't we get Paul B involved, because you are totally our of
hand.

BTW, you agreed that these options do not work, or they are not supported,
and the above configuration proves that you are wrong. AGAIN.

On Mon, Jan 7, 2013 at 10:30 PM, Brian McGahan <bmcgahan_at_ine.com> wrote:

> Hi Narbik,****
>
> ** **
>
> I would argue that your response is spam, and is not
> applicable to the list. Once again you are posting out of context free
> lab material without answering the original posters question. I could
> likewise post output from INEs lab workbooks or from Ciscos documentation
> but that is not productive. If you have technology discussion input to
> give we are more than happy to accept it.****
>
> ** **
>
> Thanks,****
>
> ** **
>
> Brian McGahan, CCIE #8593 (R&S/SP/Security)****
>
> bmcgahan_at_INE.com****
>
> ** **
>
> Internetwork Expert, Inc.****
>
> http://www.INE.com****
>
> ** **
>
> *From:* Narbik Kocharians [mailto:narbikk_at_gmail.com]
> *Sent:* Monday, January 07, 2013 11:15 PM
> *To:* ccie99999
> *Cc:* Brian McGahan; Carlos G Mendioroz; Cisco certification
>
> *Subject:* Re: preferring OSPF inter-area compared to intra-area****
>
> ** **
>
> *SORRY FOR THE LONG POST.*****
>
> ** **
>
> *Lets say we have a hub and spoke topology, where R1 is the hub router,
> and R2, R3, and R4 are the spoke routers. All the links are configured as
> P2P using the following IP addressing scheme:*****
>
> ****
>
> R1(S0/0.12)12.1.1.1/24--------------12.1.1.2(S0/0.21)R2****
>
> R1(S0/0.13)13.1.1.1/24--------------13.1.1.3(S0/0.31)R3****
>
> R1(S0/0.14)14.1.1.1/24--------------14.1.1.4(S0/0.41)R4****
>
> ****
>
> *R2 is running OSPF on its Lo0 and Lo1 with IP addresses of 2.2.2.2/8 and
> 200.2.2.2/24 respectively.*****
>
> * *****
>
> *R3 is running ospf on its Lo0 with an IP address of 3.3.3.3/8*****
>
> *R4 is running ospf on its Lo0 with an IP address of 4.4.4.4/8*****
>
> * *****
>
> *Everything is running in OSPF area 0. Lets begin:*****
>
> ****
>
> *On R1*****
>
> ****
>
> R1#Show ip route ospf | I O****
>
> *O 2.0.0.0/8 [110/65] via 12.1.1.2, 00:01:24, Serial0/0.12*****
>
> O 3.0.0.0/8 [110/65] via 13.1.1.3, 00:00:44, Serial0/0.13****
>
> O 4.0.0.0/8 [110/65] via 14.1.1.4, 00:00:14, Serial0/0.14****
>
> *O 200.2.2.0/24 [110/65] via 12.1.1.2, 00:01:24, Serial0/0.12*****
>
> ****
>
> *You can see that R1 is receiving two routes from R2, networks 2.0.0.0/8and
> 200.2.2.0/24.*****
>
> ****
>
> *Lets filter all routes coming through S0/0.12:*****
>
> ****
>
> *On R1*****
>
> ****
>
> R1(config)#*Route-map tst deny 10*****
>
> R1(config-route-map)#*match interface s0/0.12*****
>
> R1(config)#*route-map tst permit 90*****
>
> ****
>
> R1(config-route-map)#*router ospf 1*****
>
> R1(config-router)#*distribute-list route-map tst in*****
>
> ****
>
> R1#*Show ip route ospf | I O*****
>
> O 3.0.0.0/8 [110/65] via 13.1.1.3, 00:00:38, Serial0/0.13****
>
> O 4.0.0.0/8 [110/65] via 14.1.1.4, 00:00:38, Serial0/0.14****
>
> ****
>
> *Lets remove the previous solution and filter network 2.0.0.0/8 coming
> through S0/0.21 sub-interface:*****
>
> ****
>
> R1(config)#*No route-map tst*****
>
> ****
>
> R1(config)#*router ospf 1*****
>
> R1(config-router)#*No distribute-list route-map tst in*****
>
> ****
>
> R1#*Show ip route ospf | I O*****
>
> O 2.0.0.0/8 [110/65] via 12.1.1.2, 00:00:19, Serial0/0.12****
>
> O 3.0.0.0/8 [110/65] via 13.1.1.3, 00:00:19, Serial0/0.13****
>
> O 4.0.0.0/8 [110/65] via 14.1.1.4, 00:00:19, Serial0/0.14****
>
> O 200.2.2.0/24 [110/65] via 12.1.1.2, 00:00:19, Serial0/0.12****
>
> ****
>
> *The previous solution will NOT work here; to filter network 2.0.0.0/8coming
through S0/0.21 we need to do the following:
> *****
>
> ****
>
> R1(config)#*access-list 2 permit 2.0.0.0 0.255.255.255*****
>
> ****
>
> R1(config)#*route-map tst deny 10*****
>
> R1(config-route-map)#*match interface s0/0.12*****
>
> R1(config-route-map)#*match ip addr 2*****
>
> R1(config)#*route-map tst permit 90*****
>
> ****
>
> R1(config-route-map)#*router ospf 1*****
>
> R1(config-router)#*distribute-list route-map tst in*****
>
> ****
>
> R1#*Show ip route ospf | I O*****
>
> O 3.0.0.0/8 [110/65] via 13.1.1.3, 00:00:23, Serial0/0.13****
>
> O 4.0.0.0/8 [110/65] via 14.1.1.4, 00:00:23, Serial0/0.14****
>
> O 200.2.2.0/24 [110/65] via 12.1.1.2, 00:00:23, Serial0/0.12****
>
> ****
>
> *Perfect it worked, obviously the same task can be configured using
> another method.*****
>
> * *****
>
> *Lets remove the configuration from the previous solution and filter
> network 200.2.2.0/24 coming from R2, but this time we are going to use
> the IP Next-hop option:*****
>
> ****
>
> R1(config)#*No route-map tst*****
>
> R1(config)#*No access-list 2*****
>
> ****
>
> R1(config)#*router ospf 1*****
>
> R1(config-router)#*No distribute-list route-map tst in*****
>
> ****
>
> R1#*Show ip route ospf | I O*****
>
> O 2.0.0.0/8 [110/65] via 12.1.1.2, 00:00:29, Serial0/0.12****
>
> O 3.0.0.0/8 [110/65] via 13.1.1.3, 00:00:29, Serial0/0.13****
>
> O 4.0.0.0/8 [110/65] via 14.1.1.4, 00:00:29, Serial0/0.14****
>
> O 200.2.2.0/24 [110/65] via 12.1.1.2, 00:00:29, Serial0/0.12****
>
> ****
>
> *To filter using the IP next-hop option:*****
>
> ****
>
> ****
>
> R1(config)#*access-list 1 permit 200.2.2.0 0.0.0.255*****
>
> ****
>
> R1(config)#*access-list 10 permit host 12.1.1.2*****
>
> ****
>
> R1(config)#*route-map tst deny 10*****
>
> R1(config-route-map)#*match ip addr 1*****
>
> R1(config-route-map)#*match ip next-hop 10*****
>
> R1(config)#*route-map tst permit 90*****
>
> ****
>
> R1(config-route-map)#*router ospf 1*****
>
> R1(config-router)#*distribute-list route-map tst in*****
>
> ****
>
> R1#*Show ip route ospf | I O*****
>
> O 2.0.0.0/8 [110/65] via 12.1.1.2, 00:00:05, Serial0/0.12****
>
> O 3.0.0.0/8 [110/65] via 13.1.1.3, 00:00:05, Serial0/0.13****
>
> O 4.0.0.0/8 [110/65] via 14.1.1.4, 00:00:05, Serial0/0.14****
>
> * *****
>
> *Now.lets remove the previous solution and use the route-source
> option:*****
>
> ****
>
> R1(config)#*No access-list 1* ****
>
> R1(config)#*No access-list 10* ****
>
> R1(config)#*No route-map tst*****
>
> R1(config)#*router ospf 1*****
>
> R1(config-router)#*No distribute-list route-map tst in*****
>
> ****
>
> R1#*Show ip route ospf | I O*****
>
> O 2.0.0.0/8 [110/65] via 12.1.1.2, 00:00:34, Serial0/0.12****
>
> O 3.0.0.0/8 [110/65] via 13.1.1.3, 00:00:34, Serial0/0.13****
>
> O 4.0.0.0/8 [110/65] via 14.1.1.4, 00:00:34, Serial0/0.14****
>
> O 200.2.2.0/24 [110/65] via 12.1.1.2, 00:00:34, Serial0/0.12****
>
> ****
>
> * *****
>
> *To use the route-source option, we MUST use the RID of R2 in the
> access-list. To find out the RID of R2:*****
>
> ****
>
> R2#*Show ip ospf | I ID*****
>
> *Routing Process "ospf 1" with ID 0.0.0.2*****
>
> ****
>
> R1(config)#*access-list 3 permit 0.0.0.2*****
>
> R1(config)#*access-list 30 permit 200.2.2.0 0.0.0.255*****
>
> ****
>
> R1(config)#*route-map tst deny 10*****
>
> R1(config-route-map)#*match ip addr 30*****
>
> R1(config-route-map)#*match ip route-source 3*****
>
> R1(config)#*route-map tst permit 90*****
>
> R1(config-route-map)#*router ospf 1*****
>
> R1(config-router)#*distribute-list route-map tst in*****
>
> ****
>
> R1#*Show ip route ospf | I O*****
>
> O 2.0.0.0/8 [110/65] via 12.1.1.2, 00:00:06, Serial0/0.12****
>
> O 3.0.0.0/8 [110/65] via 13.1.1.3, 00:00:06, Serial0/0.13****
>
> O 4.0.0.0/8 [110/65] via 14.1.1.4, 00:00:06, Serial0/0.14****
>
> ****
>
> ****
>
> I hope this helped. ****
>
> ** **
>
> On Mon, Jan 7, 2013 at 7:09 PM, ccie99999 <ccie99999_at_gmail.com> wrote:****
>
> Thanks for your reply Brian..
>
> I see your point about filtering the RIB and not what OSPF chooses. ( I
> didn't realize this before actually)
>
> What I was complaining is that route-map matching ip next-hop or matching
> ip route-source is not working when applied with a distribute list inbound
> to ospf.
> Strange I don't find any official reference on this scenario.****
>
>
>
> On Mon, Jan 7, 2013 at 6:08 PM, Brian McGahan <bmcgahan_at_ine.com> wrote:
>
> > This filters the RIB (routing table), not the OSPF decision process. By
> > the time you apply this OSPF has already chosen the intra area route over
> > the inter area one, so all you can do is permit or deny the intra area
> one.
> >
> > The only way to really accomplish this is to make the two route types
> > equal. If you were to change the inter area route to intra area with
> > something like a virtual link or tunnel then you can modify which path is
> > preferred.
> >
>
>
> ****
>
> --
> @ccie99999****
>
>
>
> Blogs and organic groups at http://www.ccie.net
>
> _______________________________________________________________________
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>
>
>
>
>
>
> ****
>
>
>
> ****
>
> ** **
>
> -- ****
>
> *Narbik Kocharians**
> *CCSI#30832, CCIE# 12410 (R&S, SP, Security)
> *www.MicronicsTraining.com* <http://www.micronicstraining.com/>
> Sr. Technical Instructor ****
>
> YES! We take Cisco Learning Credits!
> A Cisco Learning Partner****
>

--
*Narbik Kocharians
*CCSI#30832, CCIE# 12410 (R&S, SP, Security)
*www.MicronicsTraining.com* <http://www.micronicstraining.com/>
Sr. Technical Instructor
YES! We take Cisco Learning Credits!
A Cisco Learning Partner
Blogs and organic groups at http://www.ccie.net