if you use a blank permit at the end of the statement for PBR you are going
to cause unnecessary processing on the router for unmatched traffic that
meets the requirements of the last statement which has no requirements.  All
traffic must then be processed and put back to normal routing as there is no
ACL or next hop change.  Never do this.

 

But I am going to re-copy my last email to hopefully clarify this and to
give to other new-comers on the list.

 

Kingsley,

 

It depends on what you are using it for.  Some situations you will use a
trailing route-map to permit additional traffic.  Sometimes you won't
because you are only matching on a specific condition.

 

for instance with route redistribution

route-map TAG permit 10

 match tag 86

 

If I only wanted to match on tag 86 for being redistributed I would only
have that one statement

But if I only wanted to filter if it had tag 86 then I would 

 

route-map TAG deny 10

 match tag 86

route-map TAG permit 20

 

This would permit anything that doesn't have the tag 86.  These are two
basic examples.  There are many different reasons why you would or would not
want to use a route-map without any data.

 

One other I may want to add tag 86 for network 10.1.1.0/24 and permit
everything else

 

access-list 1 permit 10.1.1.0 0.0.0.255

route-map TAG permit 10

 match access-list 1

 set tag 86

route-map TAG permit 20

 

I could go on and on like this with many different situations.  So the
answer is it depends.  Just like with vlan-maps it really does depend.  It
is not a set rule that you should add the last one with an action of
forward, (although it is typically recommended.)

 

 

Regards,

 

Tyson Scott - CCIE #13513 R&S, Security, and SP

Managing Partner / Sr. Instructor - IPexpert, Inc.

Mailto:  <mailto:[email protected]> [email protected]

Telephone: +1.810.326.1444, ext. 208

Live Assistance, Please visit:  <http://www.ipexpert.com/chat>
www.ipexpert.com/chat

eFax: +1.810.454.0130

 

IPexpert is a premier provider of Self-Study Workbooks, Video on Demand,
Audio Tools, Online Hardware Rental and Classroom Training for the Cisco
CCIE (R&S, Voice, Security & Service Provider) certification(s) with
training locations throughout the United States, Europe, South Asia and
Australia. Be sure to visit our online communities at
<http://www.ipexpert.com/communities> www.ipexpert.com/communities and our
public website at  <http://www.ipexpert.com/> www.ipexpert.com

 

From: Kingsley Charles [mailto:[email protected]] 
Sent: Wednesday, June 02, 2010 10:13 AM
To: Tyson Scott
Cc: OSL Security
Subject: Re: route-maps

 

Hi Tyson

I have already brought this topic but again want to discuss this.

With respect to CCIE security, I see the following areas where we use
route-maps

Route distribution using redistribute command with route-maps
Route filtering using distribute command with route-maps
PBR

As the end, do we need add a dummy with permit as 

route-map <name> permit 

With PBR, I don't thing it will have an effect. If you don't have it, it
will go for normal destination based routing.  If you have it, since, there
is no match statement, again
it goes for normal routing.


For filtering and redistribution, do we need to dummy permit rule? If we
have that what 
will be the effect.

Please do explain the effect of having and not having the dummy permit
statement for
PBR, router filtering and redistribution.

What should we follow from exam point of view?







With regards
Kings

On Wed, Jun 2, 2010 at 7:32 PM, Tyson Scott <[email protected]> wrote:

Just wanted to clarify as I was unsure on one of your statements below.

 

Regards,

 

Tyson Scott - CCIE #13513 R&S, Security, and SP

Managing Partner / Sr. Instructor - IPexpert, Inc.

Mailto: [email protected]

Telephone: +1.810.326.1444, ext. 208

Live Assistance, Please visit: www.ipexpert.com/chat

eFax: +1.810.454.0130

 

IPexpert is a premier provider of Self-Study Workbooks, Video on Demand,
Audio Tools, Online Hardware Rental and Classroom Training for the Cisco
CCIE (R&S, Voice, Security & Service Provider) certification(s) with
training locations throughout the United States, Europe, South Asia and
Australia. Be sure to visit our online communities at
www.ipexpert.com/communities and our public website at www.ipexpert.com
<http://www.ipexpert.com/> 

 

From: Kingsley Charles [mailto:[email protected]] 
Sent: Wednesday, June 02, 2010 10:01 AM
To: Tyson Scott
Cc: Jimmy Larsson; OSL Security


Subject: Re: [OSL | CCIE_Security] Routing when doing IOS L2L

 

I agree Tyson.

On Wed, Jun 2, 2010 at 6:24 PM, Tyson Scott <[email protected]> wrote:

Kings,

 

when you say apply it globally I assume you mean "ip local policy".  This
only affects traffic generated by the router.  The reason this is necessary
is traffic originated by the router is originated from the control plane.
PBR applied to an interface affects traffic from the data plane on the
ingress of the interface.  Thus router generated traffic can never meet this
category.

 

Interface PBR = ingress on an interface defined by your ACL in the
route-map.

local PBR = router generated traffic defined by your ACL.

 

Both of these are shown in example in the Video on Demand but I don't think
I call it out as a specific topic.  I use them to overcome some routing
problems over the DMVPN.

 

Regards,

 

Tyson Scott - CCIE #13513 R&S, Security, and SP

Managing Partner / Sr. Instructor - IPexpert, Inc.

Mailto: [email protected]

Telephone: +1.810.326.1444, ext. 208

Live Assistance, Please visit: www.ipexpert.com/chat

eFax: +1.810.454.0130

 

IPexpert is a premier provider of Self-Study Workbooks, Video on Demand,
Audio Tools, Online Hardware Rental and Classroom Training for the Cisco
CCIE (R&S, Voice, Security & Service Provider) certification(s) with
training locations throughout the United States, Europe, South Asia and
Australia. Be sure to visit our online communities at
www.ipexpert.com/communities and our public website at www.ipexpert.com
<http://www.ipexpert.com/> 

 

From: [email protected]
[mailto:[email protected]] On Behalf Of Kingsley
Charles
Sent: Wednesday, June 02, 2010 4:31 AM
To: Jimmy Larsson
Cc: OSL Security


Subject: Re: [OSL | CCIE_Security] Routing when doing IOS L2L

 

Hi Jimmy



You can find reverse-route under crypto maps. This was brought in for
redundancy. The route for remote networks will be always pointing the peer.
You need not configure the routers manually. With this, you need worry about
the route it takes to the peer.

The "set reverse-route" route was introduced later with IPSec profiles. This
allows to set tag and distance. Very useful for DVTI based VPN, where you
can redistribute using the tag.

When you apply route-maps to the interface it impacts that interface alone.
With configured globally, it impacts all interfaces.

For the problem, try this

On R1, you don't have a peer as it is a dynamic crypto map, "reverse-route
static" won't work

Just add "reverse-route" which will automatically find the peer and add the
route for 2.2.2.2

or

configure "reverse-route remote peer 172.16.1.1" with or without static
option.

or 

configure ip route 2.2.2.2 255.255.255.255 172.16.1.1

This should work.

PBR is too sophisticated solution for this issue :-)



With regards
Kings

On Wed, Jun 2, 2010 at 2:14 AM, Jimmy Larsson <[email protected]> wrote:

TacAck: The difference in route-maps between my trial and your successfull
example was that I was doing "set interface fa0/0" while you did "set ip
next-hop 172.16.1.1".  when doing it your way it works great.

 

Tyson: I understand that route-maps is not the most beautiful way of solving
things. Now I have tried it and will put that tool in the bottom of my
tool-bag. 

 

Whats the difference between applying route-maps on interface and "local"?
Do you have a good DocCD-link that I can read about route-maps? I am not a
r/s-guy (yet) and it´s quite new to me.

 

And NOW I finally understand the difference between "reverse-route" and "set
reverse-route <options>"-statements! I saw them as 2 different ways of doing
RRI but couldnt understand the difference. But when looking in the command
reference I see that "reverse-route" is the only command that ENABLES RRI,
the "set reverse-route" just tweaks the behaviour by changing distance and
so on. Cool!

 

This is cool!

 

 

 

-- 
-------
Jimmy Larsson
Ryavagen 173
s-26030 Vallakra
Sweden
http://blogg.kvistofta.nu
-------


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