Home > Ticket 11 – Redistribution Route-map (a & b)

Ticket 11 – Redistribution Route-map (a & b)

April 26th, 2018 Go to comments

On R4:
router eigrp 10
  redistribute ospf 1 route-map OSPF->EIGRP
  network 10.1.4.0 0.0.0.255
  network 10.1.10.0 0.0.0.255
  network 10.1.21.128 0.0.0.3
 default-metric 100000 100 100 1 1500
  no auto-summary
!
……
route-map OSPF_to_EIGRP deny 10
 match tag 90
route-map OSPF_to_EIGRP permit 20
  set tag 110

Ans1) R4
Ans2) IPv4 Route Redistribution
Ans3) Under the EIGRP process, delete the ‘redistribute ospf 1 route-map OSPF->EIGRP’ command and enter ‘redistribute ospf 1 route-map OSPF_to_EIGRP’ command.

Explanation for this ticket:

In this topology, we are doing mutual redistribution at multiple points (between OSPF and EIGRP on R4, DSW1 & DSW2), which is a very common cause of network problems, especially routing loops so you should use route-map to prevent redistributed routes from redistributing again into the original domain.

In this ticket, route-map is also used for this purpose. For example, the route-map “EIGRP->OSPF” is used to prevent any routes that have been redistributed into OSPF from redistributed again into EIGRP domain by tagging these routes with tag 90. These routes are prevented from redistributed again by route-map OSPF->EIGRP by denying any routes with tag 90 set.

Comments (12) Comments
  1. @ontrack
    January 12th, 2020

    I understand the concept of preventing loop via route tagging. But, I do not understand why I can´t ping from client 1 to 10.1.1.10 in R4.
    Any idea?

  2. @ontrack
    January 12th, 2020

    I just realize why

  3. kopi
    January 21st, 2020

    I was thinking the issue is different here … cause on DSW1 from “show ip eigrp topo” I can see that there is a default route 0.0.0.0/0 coming from R4 10.1.4.5, but it doesnt make it to the routing table of DSW1 … did somebody else noticed that too?

  4. Nobirabi
    January 28th, 2020

    Merhabalar,
    Dün TSHOOT sınavını geçtim. Puan 1000/1000.
    Sadece buradaki materyaller yeterli.
    NetworkTut ekibine ve burada değerli tecrübelerini paylaşan arkadaşlara çok teşekkür ederim.
    Ben de artık bir CCNP RS oldum. Hedefim CCDP and CCIE Ent.
    Herkese başarılar dilerim
    Bana gelen sorular; (24)
    Sim/simlet
    1-BGP Simulator
    2-HSRP Simlet

    Biletler:
    1-IPv4 OSPF Auhthentication
    2- NAT Case2
    3- VLAN Filter
    4- Switchport Trunk
    5- Redist. Route-map (O->E O_to_E)
    6-IPv6 OSPF Enable
    7-IP Helper Address
    8-EIGRP Passive Int.
    9-IPv6 GRE Tunnel
    10- Switchport Encapsulation

    DD
    1-Check PoE
    2- GRE Tunnel Source-Dest.

    MCQ
    1-IPv6 traffic-filter
    2-OSPF Exstart
    3-STP Cost 5
    4-uPRF Sh ip int, Sh ip traf
    5-Line console 0
    6- IPv6 Acl: 60 Permit..
    7-recursive routing
    8-uPRF: Asymmetric
    9-Different VTP domains
    10-R1 R2 GRE complete

  5. Nobirabi
    January 28th, 2020

    Hello everyone,
    I passed the TSHOOT exam yesterday. The score is 1000/1000.
    Only the materials here are enough.
    I would like to thank the NetworkTut team and friends who shared their valuable experiences here.
    I have become a CCNP RS now. My goal is CCDP and CCIE Ent.
    I wish everyone success
    Questions to me; As I wrote above.

  6. Wannapass
    February 4th, 2020

    @Nobirabi
    What do you mean NAT Case2? I only see 1 NAT ticket on networktut.

  7. KingShrek
    February 7th, 2020

    @Wannapass – There are 1 NAT ticket in networktut, but inside that ticket there are 2 possible and similar cases. Check it on ticket 4.

  8. Henry
    February 7th, 2020

    @Nobirabi,
    What is MCQ 10-R1 R2 GRE complete?

  9. KingShrek
    February 7th, 2020

    The networktut simulator R4 configuration is wrong. Pls consider to correct it, otherwise you confuse students more than help them.

    router ospf 1
    log-adjancy-changes
    …….
    redistribute eigrp 10 subnets route-map EIGRP-OSPF
    ………

    route-map EIGRP->OSPF deny 10
    match tag 110
    route-map EIGRP->OSPF permit 20 ———->>>> IT SHOWS PERMIT !!!!
    set tag 90
    route-map OSPF->EIGRP deny 10
    match tag 90
    route-map OSPF->EIGRP deny 20
    set tag 110

  10. KingShrek
    February 7th, 2020

    In my last post i mean that the R4 configuration in Network Simulator for Ticket 11b is wrong.

    route-map EIGRP->OSPF permit 20 ———->>>> IT SHOWS PERMIT !!!!

  11. 007
    February 9th, 2020

    @kingShrek it is correct ..the problem is with the OSPF route map statements

    Here is how I approached the problem
    1)Verify the problem by doing a ping from Client 1 to web server (ping to 209.65.200.241)
    2)Ping R4(next hop) from Client 1 – successful
    3)Ping R1 from Client 1 – unsuccessful
    You now now you problem is likely between R1 and R4
    4)Go to R4 and try to ping R1, webserver and client 1 – all are successful
    5)Go to R1 and try to ping R4 and Client 1 – unsuccessful
    6)Do a sh run on R4 – It tells there is router redistribution applied through a route-map
    7)Do a sh ip route eigrp -you see EIGRP 1 does not know about 10.1.1.1 and ospf 10 knows about EIGRP routes so there is a problem under redistribution of EIGRP 1
    8) Check the eigrp router configs on R4 with sh run – ther are 4 route map statements for the redistribution.

    Redistribution is based on what is in the routing table. We are using the
    route map named EIGRP->OSPF deny 10
    metric tag 110 =====> to deny any eigrp routes that have been tagged with a metric of 110 from being redistributed again back into ospf
    route map named EIGRP->OSPF permit 20
    metric tag 90 ====> allows eigrp routes that have been tagged with a metric of 90(not yet been redistributed) to be redistributed into OSPF

    the second set of route map statements concern OSPF redistribution into EIGRP
    route map named OSPF->EIGRP deny 10
    metric tagged 90 ====> this denies any OSPF routes which now have a tag of 90 from being redistributed into EIGRP again and
    route-map named OSPF->EIGRP deny 20
    metric tag 110 ====> also denies OSPF routes with an AD of 110 that have not yet been redistributed from being redistributed int eigrp and THERE IS THE PROBLEM…IT should permit undistributed ospf routes with a tag of 110 to be allowed for redistribution hence the correct answer is

    route map named OSPF->EIGRP permit 20
    metric tag 110

    The deny statements prevent EIGRP/OSPF routes that have already been redistributed form being redistributed again while the permit statements allow undistributed EIGRP/OSPF routes to be redistributed as required

  12. zeh
    February 10th, 2020

    @KingShrek está correto, verifiquem a questão 11b no networktut simulator R4 a configuração está errada