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Policy Based Routing Sim

February 8th, 2015 in Lab Sim, LabSim Go to comments

Question

Company TUT has two links to the Internet. The company policy requires that web traffic must be forwarded only to Frame Relay link if available and other traffic can go through any links. No static or default routing is allowed.

BGP_Policy_Based_Routing_Sim.jpg

 

Answer and Explanation:

Notice: The answer and explanation below are from PeterPan and Helper.Please say thank to them!

All the HTTP traffic from the EIGRP Network should go through Frame Relay link if available and all the other traffic should go through either link.
The only router you are able to administrate is the Border Router, from the EIGRP Network you may only send HTTP traffic. As the other people mentioned, actually it is not a BGP lab. You are not able to execute the command “router bgp 65001”

1) Access list that catches the HTTP traffic:
BorderRouter(config)#access-list 101 permit tcp any any eq www

Note that the server was not directly connected to the Border Router. There were a lot of EIGRP routes on it. In the real exam you do not know the exact IP address of the server in the EIGRP network so we have to use the source as “any” to catch all the source addresses.

2) Route map that sets the next hop address to be ISP1 and permits the rest of the traffic:
BorderRouter(config)#route-map pbr permit 10
BorderRouter(config-route-map)#match ip address 101
BorderRouter(config-route-map)#set ip next-hop 10.1.101.1
BorderRouter(config-route-map)#exit

(Update: We don’t need the last command route-map pbr permit 20 to permit other traffic according to Cisco:

“If the packets do not meet any of the defined match criteria (that is, if the packets fall off the end of a route map), then those packets are routed through the normal destination-based routing process. If it is desired not to revert to normal forwarding and to drop the packets that do not match the specified criteria, then interface Null 0 should be specified as the last interface in the list by using the set clause.”

Reference: http://www.cisco.com/en/US/products/ps6599/products_white_paper09186a00800a4409.shtml)

Note: We don’t need to use IP SLA to track the next-hop IP address as the “set ip next-hop” did this. From this link: https://www.cisco.com/c/en/us/support/docs/ip/ip-routed-protocols/47121-pbr-cmds-ce.html
“The set ip next-hop command verifies the existence of the next hop specified, and…
+ If the next hop exists in the routing table, then the command policy routes the packet to the next hop.
+ If the next hop does not exist in the routing table, the command uses the normal routing table to forward the packet.”
So if the next-hop 10.1.101.1 goes down the PBR will use normal routing table.

3) Apply the route-map on the interface to the server in the EIGRP Network:
BorderRouter(config-route-map)#exit
BorderRouter(config)#int fa0/0
BorderRouter(config-if)#ip policy route-map pbr
BorderRouter(config-if)#exit
BorderRouter(config)#exit

4) There is a “Host for Testing”, click on this host to open a box in which there is a button named “Generate HTTP traffic”. Click on this button to generate some packets for HTTP traffic. Jump back to the BorderRouter and type the command “show route-map”.

BorderRouter#show route-map

In the output you will see the line “Policy routing matches: 9 packets…”. It means that the route-map we configured is working properly.

Note: We have posted a Policy Based Routing lab on GNS3 similar to this sim with detailed explanation, you can read it here.

Other lab-sims on this site:

EIGRP Stub Sim

OSPF Sim

EIGRP OSPF Redistribution Sim

IPv6 OSPF Virtual Link Sim

EIGRP Simlet

Comments
Comment pages
1 2 28
  1. fiddy
    October 15th, 2017

    Hi All,

    I have tried to open route Exam sims in GNS v1.5.2 but after opening topology all nodes in the topology turned red , when I click over the node it says ” This node is not initialized”

    Can someone please know how to fix this so that I can practice these exam labs ?? or any other way to practice these labs

  2. mario5046
    October 16th, 2017

    @Tej you missed just only one lab PBR ? What about the rest of questions , there you also made some mistakes?

  3. Mpolvora
    October 20th, 2017

    hello kristen hellin

    Could you send me the dumps please?
    Thank you very much
    {email not allowed}

  4. Mpolvora
    October 20th, 2017

    hello kristen hellin

    Could you send me the dumps please?
    Thank you very much
    mpolvoratjp @ gmail.com

  5. Chikku
    October 29th, 2017

    Anyone who took the exam recently can confirm which are the SIMs in the exam?????
    I’m gonna take it early next week.
    Please respond asap.

  6. Silver Star
    October 30th, 2017

    taking Exam Tomorrow, will provide feedback, have no idea which drag and drops will appear and have not studied any

  7. Chikku
    October 31st, 2017

    @SILVER STAR, Please check the drag and drop in digitaltut site itself. Hope this would suffice.
    BGP states, Nat64, NPT64, CEF adjacency types…

  8. Confused
    November 1st, 2017

    Host_For_Testing>en
    Host_For_Testing#telnet 10.1.101.1 80
    Trying 10.1.101.1, 80 …
    % Destination unreachable; gateway or host down

    Host_For_Testing#telnet 10.1.102.1 80
    Trying 10.1.102.1, 80 … Open
    ^C

    same commands as above , i am practicing in GNS3 labs here in this site. but it shows the opposite output. Can anybody help.

  9. Alpha
    November 4th, 2017

    Hello everyone. Can anyone help me by telling that 462q are still valid or not ?

  10. Alpha
    November 4th, 2017

    Response awaited.

  11. EU
    November 4th, 2017

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  12. EU
    November 4th, 2017

    Hello Lemo,
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  13. XXX
    November 7th, 2017

    Passed with 918/1000.
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  14. ZBM
    November 8th, 2017

    Hey Elmo kindly share the dump with me on “{email not allowed}” congrats hope you ready for the next task.

  15. Ray
    November 18th, 2017

    Hi Please send me a copy of update Dumps.

  16. FirePOWDER
    November 20th, 2017

    Hi Please sent to me VCE Update Dumps. Thx guy.
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  17. Erol
    November 26th, 2017

    Tried this in GNS3 and it works:

    – The first ‘set’ tries the 10.1.100.2 ISP 1 interface, and takes to the other if it’s not there.
    – The second ‘set’ sends all non TCP80 traffic to ISP 2

    You can see what happens at the various routers with

    – access-list 1 permit 172.16.14.2
    – debug ip pack 1

    Config on R1:

    access-list 101 permit tcp any any eq www
    !
    route-map PBR permit 10
    match ip address 101
    set ip next-hop 10.1.100.2 10.1.101.2
    !
    route-map PBR permit 20
    set ip next-hop 10.1.101.2
    !
    int f0/0
    ip policy route-map PBR

  18. Erol
    November 26th, 2017

    This is the accompanying output of a ‘debug ip policy’ on the Border Router that indicates what happens as soon as the link to ISP1 becomes unavailable. It uses CEF’s FIB to address any next-hop issues.

    The ‘Host for testing’, a GNS3 VPCS, generates TCP80 traffic by pinging a non-local ip address by using the following command: ping 1.1.1.1 -p 80 -3 -t

    As you can see at first this traffic is policy-based routed towards ISP1. As soon as CEF discovers that the next-hop ip address (ISP1 via interface S2/0 in my setup) is not reachable anymore, the ISP2 next-hop ip address 10.1.101.2 is chosen instead.

    *Nov 26 10:34:32.100: IP: s=172.16.14.2 (Ethernet0/1), d=11.1.1.1, len 60, FIB policy match
    *Nov 26 10:34:32.100: IP: s=172.16.14.2 (Ethernet0/1), d=11.1.1.1, len 60, PBR Counted
    *Nov 26 10:34:32.100: IP: s=172.16.14.2 (Ethernet0/1), d=11.1.1.1, g=10.1.100.2, len 60, FIB policy routed
    R1#
    *Nov 26 10:34:33.101: IP: s=172.16.14.2 (Ethernet0/1), d=11.1.1.1, len 60, FIB policy match
    *Nov 26 10:34:33.101: IP: s=172.16.14.2 (Ethernet0/1), d=11.1.1.1, len 60, PBR Counted
    *Nov 26 10:34:33.101: IP: s=172.16.14.2 (Ethernet0/1), d=11.1.1.1, g=10.1.100.2, len 60, FIB policy routed
    R1#
    *Nov 26 10:34:34.352: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial2/0, changed state to down
    R1#
    *Nov 26 10:34:35.102: IP: s=172.16.14.2 (Ethernet0/1), d=11.1.1.1, len 60, FIB policy match
    *Nov 26 10:34:35.102: IP: s=172.16.14.2 (Ethernet0/1), d=11.1.1.1, len 60, PBR Counted
    *Nov 26 10:34:35.102: CEF-IP-POLICY: fib for addr 10.1.100.2 is Not Attached; Nexthop rejected
    *Nov 26 10:34:35.102: IP: s=172.16.14.2 (Ethernet0/1), d=11.1.1.1, g=10.1.101.2, len 60, FIB policy routed
    *Nov 26 10:34:36.103: IP: s=172.16.14.2 (Ethernet0/1), d=11.1.1.1, len 60, FIB policy match
    *Nov 26 10:34:36.104: IP: s=172.16.14.2 (Ethernet0/1), d=11.1.1.1, len 60, PBR Counted
    *Nov 26 10:34:36.104: CEF-IP-POLICY: fib for addr 10.1.100.2 is Not Attached; Nexthop rejected

    You can see the TCP80 traffic arriving at ISP1 or ISP2 routers by using a ‘debug ip packet 1’ command, whereas ‘1’ is a standard access-list that permits traffic from the Testing Host at 172.16.14.2.

    When non-TCP80 traffic is generated, all traffic goes to ISP2.

    Also you can use the ‘show ip policy’- command on the Border Router to see counters incrementing on hits.

  19. Erol
    November 26th, 2017

    If you omit the ‘set ip next-hop 10.1.101.2’, in the ‘route-map PBR permit 20’, non-TCP80 is not explicitly routed to ISP2 anymore but follows normal forwarding rules, as you would probably want :)

    Config now reads:

    route-map PBR permit 10
    match ip address 101
    set ip next-hop 10.1.100.2 10.1.101.2
    !
    route-map PBR permit 20
    !
    !
    access-list 101 permit tcp any any eq www
    !

    When i generate some non-TCP80 traffic i see the following in a debug ip policy on the Border Router:

    *Nov 26 11:06:38.748: IP: s=172.16.14.2 (Ethernet0/1), d=11.1.1.1, len 60, FIB policy match
    *Nov 26 11:06:38.748: IP: s=172.16.14.2 (Ethernet0/1), d=11.1.1.1, len 60, PBR Counted
    *Nov 26 11:06:38.748: IP: s=172.16.14.2 (Ethernet0/1), d=11.1.1.1, len 60, FIB policy rejected – normal forwarding

    Look at the incrementing counters of the ‘show ip policy’-command on the Border Router. Using the ‘debug ip policy’ command first, gives some nice extra output about Nexthop Tracking on the ‘show ip policy’-command, that you wouldn’t get without the debug command.

    R1#sh route-map
    route-map PBR, permit, sequence 10
    Match clauses:
    ip address (access-lists): 101
    Set clauses:
    ip next-hop 10.1.100.2 10.1.101.2
    Nexthop tracking current: 0.0.0.0
    10.1.100.2, fib_nh:0,oce:0,status:0

    10.1.101.2, fib_nh:0,oce:0,status:0

    Policy routing matches: 196 packets, 14504 bytes
    route-map PBR, permit, sequence 20
    Match clauses:
    Set clauses:
    Policy routing matches: 84 packets, 6216 bytes

  20. ali
    January 13th, 2018

    how can we measure network ip in this lab cany anyone explain please

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    January 17th, 2018

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  22. Anonymous
    January 19th, 2018

    @Erol, why we need route-map permit 20 at the end of route-map? pleeeeeeeease someone explain im really confused

  23. shabnam
    January 19th, 2018

    since this is the frame-relay link u cant know rechibility of next-hop with policy base routing, imaging link between frame-relay cloud and ISP fail, ur router wont be able to detect next-hop failure bcoz it’s receiving keepalive fram frame-relay switch ……
    u can lab it in gns3 ad u will see the result
    so u need configure ip sla and verify rechibility with icmp-echo

  24. Clock
    January 21st, 2018

    Hello Team,

    I would like to thank you for the advises and that you share your experience, I recently pass the route exam :D….
    I study with the Official cert Kevin Wallace, CBT nuggets (nothing that you cannt find for your own in a torrent) and with this site.
    I can say that I found a couple of new questions and a new Frame relay drag and drop that is not here:

    SVC —— A circuit that provides temporary on-demand connections between DTEs
    DLCI—— A locally significant ID
    PVC ——-A logical connection comprising two endpoints and CIR
    LMI ——- A signaling mechanism for frame relay devices
    FECN—– An indicator of congestion on the network.

    But this does not mean you will not pass the exam for 2 questions.

    Please do not pay for dumps or believe in guys who post “new dump” or “I have the new dump”, or “I failed the exam”, those guys should be rape and kill!!!!!!

    Anyway, hope you pass the exam and share your real experience for the other exams..

  25. Przemek
    January 23rd, 2018

    Hi All, Passed today 905 pts.
    About 5 newer questions then on digital.tut.
    On Policy Based Routing Sim there was no automtic filling commands (TAB) during creating ACL, so you can learn it in details.
    Command: ()#access-list 105 permit tcp any any eq 80 works fine.

    I learnt from digitaltut and IT Libraries dated 07.2017 (417q) and CBT.
    Thanks all for sharing experience.

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    January 23rd, 2018

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    January 24th, 2018

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    January 25th, 2018

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    January 26th, 2018

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  32. Rhymer
    February 4th, 2018

    Hi, Passed my CCNP route 300-101 today. score 8xx. Thing is very few practise questions, not even one from BGP. So please focus on the theory. there was a question from PPPoE regarding the states PADI, PADR, PADO. Thankfully Lab Sims were as on this site, PBR, EIGRP Stub and OSPF n EIGRP redistribution. Few new drag and drop questions were there including functions of global address, multicast address, address registration, virtual address. I feel if you work well on the lab sims you can pass. Good luck.

  33. Confuse guy
    February 14th, 2018

    The company policy requires that web traffic

    DOes this means we need to enable http and https?
    The answer given only enable http(www=80). Am I right

  34. Anonymous
    February 18th, 2018

    Dear How to generate HTTP traffic ?

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