Re: How would you solve this task?

It seems there is quite a bit of information out there saying if you disable
auto-summary in EIGRP that the summary routes to null0 go away. To double
check my sanity I have just labbed this up, and again the common belief is
not consistent with my test

R2#sh ip int brie | exc unass
Interface IP-Address OK? Method Status
Protocol
FastEthernet0/0 12.12.12.2 YES NVRAM up
down
Serial0/1/0.204 24.24.24.2 YES NVRAM up
up
Serial0/1/0.205 25.25.25.2 YES NVRAM down
down
Loopback0 2.2.2.2 YES NVRAM up
up

R2#sh run | b router eigrp
router eigrp 1
 passive-interface default
 no passive-interface Serial0/1/0.204
 network 2.2.2.2 0.0.0.0
 network 24.24.24.2 0.0.0.0
 no auto-summary

interface Serial0/1/0.204 point-to-point
 ip address 24.24.24.2 255.255.255.0
 ip summary-address eigrp 1 2.2.0.0 255.255.0.0 5
 snmp trap link-status
 frame-relay interface-dlci 204

R2#sh ip ro e
     2.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
D 2.2.0.0/16 is a summary, 00:00:38, Null0

On Tue, Aug 9, 2011 at 12:50 PM, Joe Astorino <joeastorino1982_at_gmail.com>wrote:

> Good question. My view with EIGRP is that there is absolutely no reason to
> NOT disable auto summarization unless you have a really really good reason
> (i.e. the lab says so). Disabling auto-summary should be a given every time
> you type "router eigrp". With that being said, I think the solutions guide
> you have is wrong. Disabling auto-summarization in EIGRP does not disable
> summary routes to null0, at least in the recent experiments I have done.
>
> I think your solution of changing the AD on the summary to 255 is a fine
> solution and it meets the requirements of the task.
>
> Check out this blog:
> http://astorinonetworks.com/2011/07/20/summary-routes-to-null0-the-protocols-that-love-them/
>
>
>
>
> On Tue, Aug 9, 2011 at 12:46 PM, Daniel Dib <daniel.dib_at_reaper.nu> wrote:
>
>> On ti, aug 09, 2011 at 17:31:46, Joe Astorino wrote:
>> > Cc: ccielab_at_groupstudy.com
>> > Subject: Re: How would you solve this task?
>> >
>> > Lots of great advice in this thread, but here is my two cents. I like
>> > your solution better. It is more specific and in my opinion more
>> > technically correct. However, that is not the point of my post. The
>> > point is, this is a task that is a great example of when to clarify
>> > with the proctor. Make sure you choose your words carefully. I might
>> > have said something like "This task wants me to log successful and
>> > unsuccessful telnet attempts. I believe there are multiple ways to
>> > define a telnet attempt. For example, I could simply log all packets
>> > destined for the well known telnet port of TCP 23, or I could be very
>> > specific and log login success/failures using the login feature set.
>> > Could you clarify which would be more acceptable, or does it matter?"
>> >
>> > HTH
>> >
>>
>> Hi Joe,
>>
>> Great advice. What would you recommend for the task below:
>>
>> 1.10 TROUBLE TICKET 10
>> R1's routing table has a summary pointing to Null0. Modify R1 so that
>> there
>> are no routes to Null0.
>>
>> SG solution: Turn off auto-summary under EIGRP.
>>
>> My solution: Announce summary with AD of 255 on Ethernet interface which
>> meant it is not installed locally with the ip summary address eigrp
>> command.
>> If the task had said something like make sure that classless routing is
>> used
>> or anything like that I would definitely have removed auto-summary. Maybe
>> it
>> is a safe assumption that auto-summary should not be used unless a task
>> tells you to, guess that is one more for the proctor.
>>
>> Also one of those tasks that could easily get misinterpreted.
>>
>> Once again, thanks for your input.
>>
>>
>> /Daniel
>>
>>
>
>
> --
> Regards,
>
> Joe Astorino
> CCIE #24347
> Blog: http://astorinonetworks.com
>
> "He not busy being born is busy dying" - Dylan
>
>

-- 
Regards,
Joe Astorino
CCIE #24347
Blog: http://astorinonetworks.com
"He not busy being born is busy dying" - Dylan
Blogs and organic groups at http://www.ccie.net