5.26 EIGRP Filtering with Route Maps


* Configure a route-map filter on R3 that denies EIGRP routes with a metric in the range of 500,000 - 750,000 from entering the routing table.

* These filters should no impact any other networks advertised by R4 or learned by R2 and R3.


Is it just me, or this task leads into configuring route-map match-all for r3 with 2 statement inside - to match that the route is tagged and to make sure that it has a metric in a range of 625k+-125k?

So it's either question bad wording, config incorrect or I'm confused.


  • I think its not errata, config are good. Only if some one can explain in more detail about how this +- thing work, it will be great.


    Best Regards,


    Nadeem Rafi

  • 625000 +- 125000 will give you the range of 500000 - 700000. Its plus/minus your first value to your second value. Hope this helps. :)

  • Or range of 500,000 to 750,000 if you do your maths correctly :)

    On 3 March 2010 03:58, bluejose <[email protected]> wrote:

    625000 +- 125000 will give you the range of 500000 - 700000. Its plus/minus your first value to your second value. Hope this helps. :)

    View this message online at: http://ieoc.com/forums/p/8359/106070.aspx#106070

  • Oops... you are definitly correct. :) Thx

  • I just wonder when there would be an issue, in case you have 500000 + 250000 configured.

    I did that and it leads to the same result as the case solution.

    If anyone can think of a situation where this may cause issues, please comment on this.


  • Also the redistribute command under router eigrp 100 seems to have wrong delay value. The delay value should be 10 and not 100 as delay is represented in tens of microseconds. Similar correct statement is given under example 5.8 also.

    The correct redistribute statement under R4 should be

    router eigrp 100

    redistribute rip 100000 10 255 1 1500 route-map RIP_TO_EIGRP

  • I just have small questions :

    why do we configure two route-maps clauses for R4 like this :


    *route-map rip_to_eigrp permit 10

    match ip address prefix-list vlan43

    set tag 4


    *route-map rip_to_eigrp permit 20


    ~second clause for allow all ?

  • Hi unsobill,

    That is correct, the last clause is used to permit all. Always remember that there is a deny all in the end, so if you don't specify the last clause, it will set tag 4 for VLAN43 and it will filter all the others. By using the permit 20 in the end, you are setting the tag4 for VLAN43 and permiting all the other routes, leaving them untouched.


  • Just thought that I would share a simple formula in order to work out the calculation:

    match metric <START METRIC> +- <RANGE METRIC>



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