Re: Recursive Routing and Tunnels

From: ALL From_NJ (all.from.nj@gmail.com)
Date: Sun Feb 22 2009 - 03:08:02 ARST

Yep, you are right, will do; thanks.

Any additional comments on the recursive routing ... agree with the method
of 'solving' it?

Many TIA,

Andrew

On Sun, Feb 22, 2009 at 12:05 AM, Jason Madsen <madsen.jason@gmail.com>wrote:

> no, the command is distribute list out...not data-base filter. you can do
> it on ASBRs for external routes. try it out.
>
> Jason
>
> On Sat, Feb 21, 2009 at 10:03 PM, ALL From_NJ <all.from.nj@gmail.com>wrote:
>
>> Yeah ... I seem to remember something about this distribute list rule ...
>> Thanks for mentioning this.
>>
>> The command:
>> ip ospf database-filter all out
>>
>> This command filters the LSA outgoing, but ... it is not a distribute
>> list.
>>
>>
>>
>>
>> On Sun, Feb 22, 2009 at 12:00 AM, Jason Madsen <madsen.jason@gmail.com>wrote:
>>
>>> you can do them outbound if you're an ASBR.
>>>
>>> Jason
>>>
>>> On Sat, Feb 21, 2009 at 9:56 PM, Jason Morris <mcnever@gmail.com>wrote:
>>>
>>>> something to keep in mind about how ospf distribute lists work
>>>>
>>>> you can never do a distribute list OUT with OSPF.
>>>>
>>>> OSPF filters LSAs from the ospf database to the routing table vs
>>>> filtering
>>>> routes advertised or recieced from a neightbor like eigrp or rip does.
>>>>
>>>> all the databases in an area have to have the same info or ospf can't
>>>> calculate paths correctly.
>>>>
>>>> if that makes since.
>>>>
>>>> jason
>>>>
>>>>
>>>>
>>>> On Sat, Feb 21, 2009 at 11:35 PM, ALL From_NJ <all.from.nj@gmail.com>
>>>> wrote:
>>>>
>>>> > Interesting lab testing tonight, was playing w/ tunnel interfaces and
>>>> OSPF.
>>>> >
>>>> >
>>>> > I had a scenario I was practicing, basically it was:
>>>> >
>>>> > NBMA w/ network type of non-broadcast. Can not use neighbor command
>>>> or
>>>> > make
>>>> > any config changes to the physical interface on either sides.
>>>> >
>>>> > So I created a tunnel and added it to OSPF.
>>>> >
>>>> > As you would expect, recursive routing began to occur.
>>>> >
>>>> > Here is a nifty debug output which quickly showed why the neighbor
>>>> bounces:
>>>> >
>>>> > R2#debu ip ospf adj
>>>> > OSPF adjacency events debugging is on
>>>> >
>>>> > *Mar 1 04:34:36.531: %TUN-5-RECURDOWN: Tunnel1 temporarily disabled
>>>> due to
>>>> > recursive routing
>>>> > *Mar 1 04:34:37.531: %LINEPROTO-5-UPDOWN: Line protocol on Interface
>>>> > Tunnel1, changed state to down
>>>> > *Mar 1 04:34:37.531: OSPF: Interface Tunnel1 going Down
>>>> >
>>>> > I know one answer to solve this is to simply remove the physical
>>>> link's
>>>> > network address from OSPF. Odd learning though, as I tried to
>>>> configure
>>>> > other method of filters.
>>>> >
>>>> > OSPF would not take a distribute list OUT for the tunnel interface ...
>>>> > figured I would simply keep the local physical link's network from
>>>> being
>>>> > advertised out via the tunnel. No-go on this.
>>>> >
>>>> > OSPF did take a Distribute list IN via the tunnel. I denied the local
>>>> > link's network ... and all was well in la-la land (where I live).
>>>> >
>>>> > R1(config-router)#distribute-list 12 in tunnel 1
>>>> >
>>>> > Would have been easier and quicker for me to simply remove the
>>>> physical
>>>> > link's network from OSPF, but I was / am learning ...
>>>> >
>>>> > Also, ... I actually prefer a distribute list IN, since if I am able
>>>> to
>>>> > keep
>>>> > the physical link's network in OSPF on my hub router, other peers will
>>>> > still
>>>> > learn about it. I am only filtering via these two routers, and all
>>>> other
>>>> > routers still learn about the local link's network.
>>>> >
>>>> > Question for the group:
>>>> >
>>>> > For recursive learning, any additional thoughts on ways for me to
>>>> learn
>>>> > this
>>>> > / explore this / solve this?
>>>> >
>>>> > I suppose in all of life, the kiss method is the best ... Just
>>>> figured I
>>>> > would ping yall to see what insights I might learn.
>>>> >
>>>> > Many TIA,
>>>> >
>>>> > Andrew Lee Lissitz
>>>> >
>>>> > --
>>>> > Andrew Lee Lissitz
>>>> > all.from.nj@gmail.com
>>>> >
>>>> >
>>>> > Blogs and organic groups at http://www.ccie.net
>>>> >
>>>> >
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>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>
>>
>> --
>> Andrew Lee Lissitz
>> all.from.nj@gmail.com
>>
>
> 

-- 
Andrew Lee Lissitz
all.from.nj@gmail.com

Blogs and organic groups at http://www.ccie.net

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