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  1. #1
    Join Date
    Jul 2011
    Posts
    8

    Default Trouble with Lab 13.1

    I cannot ping ISP to Lab C router. They are both in the same subnet and range, I don't see why they cannot ping. Can it be the interfaces?

    Here is my topology on PAcket Tracer.

    http://www.megaupload.com/?d=PJK5146W

    Help would be much appreciated here. Thank you.
    Test day: August 23rd

  2. #2
    Join Date
    Apr 2011
    Posts
    16

    Default

    I'm in the same scenario. Without looking at your topology, I think there might be a typo on the page. Here's why: the book lists the line passive-interface s0/2 as part of the configuration for Lab_A. Todd explains that this will prevent RIP updates from propagating back to the ISP router connected on that interface.
    From what I can see in the configuration, you should be able to ping from ISP to Lab_A, Lab_A to Lab_C and Lab_C to ISP.
    Anyone else care to weigh in on the topic?

  3. #3
    Join Date
    Apr 2011
    Posts
    16

    Default

    Update: I have another problem with the lab. I can't ping ISP from any router that isn't directly attached to ISP. Inspection of the routing table from Lab_C shows:

    R 171.16.0.0/16 [120/2] via 192.168.30.1

    The lab description of ISP shows that it should be a /24 but RIP is sending it as a /16. I have tried setting network 171.16.10.0 in router rip but it automatically gets changed to 171.16.0.0 in the running config
    Last edited by Scottmeup; 10-03-2011 at 06:19 PM.

  4. #4
    Join Date
    Dec 2006
    Posts
    2,198

    Default

    did you configure the "no auto-summary" command?
    Todd

  5. #5
    Join Date
    Apr 2011
    Posts
    16

    Default

    Thanks for the reply Todd. I didn't have no auto-summary configured previously, I have now but the results are the same. My RIP configuration now looks like this

    Code:
     router rip
     version 2
     passive-interface Serial0/0/0
     network 171.16.0.0
     network 192.168.20.0
     no auto-summary
    The last commands I ran in RIP were
    Lab_A(config-router)#no network 171.16.0.0
    Lab_A(config-router)#network 171.16.10.0


    For the purpose of this lab could I simply reconfigure the 17.16.10.0/24 network to be a /16 on Lab_A and ISP?

  6. #6
    Join Date
    Apr 2011
    Posts
    16

    Default

    I'm still having a hard time with this one! I've got a lab based on 13.1 where i've replaced the serial links with copper, and replaced the 171.16.10.0/24 with a 171.16.10.0/16.
    After setting up RIP but before running the passive-interface and default-network commands I can ping from Lab_C to ISP and back again.
    After I run the passive-interface and ip default-network commands I can no longer ping from Lab_C or Lab_B to ISP.

    I'd be happy to post topology / config files! Can anyone help?

  7. #7
    Join Date
    Aug 2011
    Location
    Plano, TX
    Posts
    92

    Default

    Sure. Post'em!

    _______________ _______________ _______________ _______________ _
    CCNA

  8. #8
    Join Date
    Apr 2011
    Posts
    16

    Default

    Here you go thanks for the interest! All passwords are cisco.

    I've modified the lab 13.1 in the book: changed the 171.16.10.0/24 to 171.16.10.0/16, changed the serial links to copper crossovers and ran default-information originate on Lab_A because RIP wasn't distributing 0.0.0.0 without it! I still can't ping ISP from Lab_B and Lab_C though


    Code:
    !
    version 12.4
    no service timestamps log datetime msec
    no service timestamps debug datetime msec
    no service password-encryption
    !
    hostname ISP
    !
    !
    !
    enable secret 5 $1$mERr$hx5rVt7rPNoS4wqbXKX7m0
    enable password cisco
    !
    !
    !
    !
    !
    !
    !
    !
    !
    !
    !
    !
    !
    !
    !
    !
    interface FastEthernet0/0
     ip address 171.16.10.1 255.255.0.0
     duplex auto
     speed auto
    !
    interface FastEthernet0/1
     no ip address
     duplex auto
     speed auto
     shutdown
    !
    interface Vlan1
     no ip address
     shutdown
    !
    router rip
     network 171.16.0.0
    !
    ip classless
    !
    !
    !
    !
    !
    !
    !
    line con 0
     exec-timeout 0 0
     logging synchronous
    line vty 0 4
     password cisco
     login
    line vty 5 15
     password cisco
     login
    !
    !
    !
    end
    Code:
    !
    version 12.4
    no service timestamps log datetime msec
    no service timestamps debug datetime msec
    no service password-encryption
    !
    hostname Lab_A
    !
    !
    !
    enable secret 5 $1$mERr$hx5rVt7rPNoS4wqbXKX7m0
    enable password cisco
    !
    !
    !
    !
    !
    !
    !
    !
    !
    !
    !
    !
    !
    !
    !
    !
    interface FastEthernet0/0
     ip address 171.16.10.2 255.255.0.0
     duplex auto
     speed auto
    !
    interface FastEthernet0/1
     ip address 192.168.20.1 255.255.255.0
     duplex auto
     speed auto
    !
    interface Vlan1
     no ip address
     shutdown
    !
    router rip
     passive-interface FastEthernet0/0
     network 171.16.0.0
     network 192.168.20.0
     default-information originate
    !
    ip classless
    ip route 0.0.0.0 0.0.0.0 FastEthernet0/0 
    !
    !
    !
    !
    !
    !
    !
    line con 0
     exec-timeout 0 0
     logging synchronous
    line vty 0 4
     password cisco
     login
    line vty 5 15
     password cisco
     login
    !
    !
    !
    end
    Code:
    !
    version 12.4
    no service timestamps log datetime msec
    no service timestamps debug datetime msec
    no service password-encryption
    !
    hostname Lab_B
    !
    !
    !
    enable secret 5 $1$mERr$hx5rVt7rPNoS4wqbXKX7m0
    enable password cisco
    !
    !
    !
    !
    !
    !
    !
    !
    !
    !
    !
    !
    !
    !
    !
    !
    interface FastEthernet0/0
     ip address 192.168.20.2 255.255.255.0
     duplex auto
     speed auto
    !
    interface FastEthernet0/1
     ip address 192.168.30.1 255.255.255.0
     duplex auto
     speed auto
    !
    interface Vlan1
     no ip address
     shutdown
    !
    router rip
     network 192.168.20.0
     network 192.168.30.0
    !
    ip classless
    !
    !
    !
    !
    !
    !
    !
    line con 0
     exec-timeout 0 0
     logging synchronous
    line vty 0 4
     password cisco
     login
    line vty 5 15
     password cisco
     login
    !
    !
    !
    end
    Code:
    !
    version 12.4
    no service timestamps log datetime msec
    no service timestamps debug datetime msec
    no service password-encryption
    !
    hostname Lab_C
    !
    !
    !
    enable secret 5 $1$mERr$hx5rVt7rPNoS4wqbXKX7m0
    enable password cisco
    !
    !
    !
    !
    !
    !
    !
    !
    !
    !
    !
    !
    !
    !
    !
    !
    interface FastEthernet0/0
     ip address 192.168.30.2 255.255.255.0
     duplex auto
     speed auto
    !
    interface FastEthernet0/1
     no ip address
     duplex auto
     speed auto
     shutdown
    !
    interface Vlan1
     no ip address
     shutdown
    !
    router rip
     network 192.168.30.0
    !
    ip classless
    !
    !
    !
    !
    !
    !
    !
    line con 0
     exec-timeout 0 0
     logging synchronous
    line vty 0 4
     password cisco
     login
    line vty 5 15
     password cisco
     login
    !
    !
    !
    end
    Attached Files Attached Files

  9. #9
    Join Date
    Aug 2011
    Location
    Plano, TX
    Posts
    92

    Default

    On Lab A try

    ip route 0.0.0.0 0.0.0.0 171.16.10.1

    _______________ _______________ _______________ _______________ _______
    CCNA

  10. #10
    Join Date
    Apr 2011
    Posts
    16

    Default

    Thank you for the reply! I've removed all static routes from Lab_A and added the line ip route 0.0.0.0 0.0.0.0 171.16.10.1. The output from Lab_B is:

    Code:
    Gateway of last resort is 192.168.20.1 to network 0.0.0.0
    
    R    171.16.0.0/16 [120/1] via 192.168.20.1, 00:00:16, FastEthernet0/0
    C    192.168.20.0/24 is directly connected, FastEthernet0/0
    C    192.168.30.0/24 is directly connected, FastEthernet0/1
    R*   0.0.0.0/0 [120/1] via 192.168.20.1, 00:00:16, FastEthernet0/0
    Lab_B#ping 171.16.10.1
    
    Type escape sequence to abort.
    Sending 5, 100-byte ICMP Echos to 171.16.10.1, timeout is 2 seconds:
    .....
    Success rate is 0 percent (0/5)
    
    Lab_B#
    Lab_A can still ping 171.16.10.1! I'm confused

    I've done a tracerout from Lab_C and everything hits the 192.168.30.0 network, then the 192.168.20.0 network but gives up there and just times out!
    I could ping 171.16.10.1 until I ran the passive interface s0/0 command.
    Last edited by Scottmeup; 10-08-2011 at 06:19 PM.

  11. #11
    Join Date
    Aug 2011
    Location
    Plano, TX
    Posts
    92

    Default

    Your ISP router does not know what to do with packets destined for network 192.168.20.0/24 because you made the outbound interface from Lab A passive.

    You have a number of options to fix this:

    1. Add a static route on ISP to 192.168.20.0/24 via Lab A
    2. Advertise routes from Lab A to ISP
    3. Enable NAT on Lab A

    You should do each to make sure you understand what's going on.

    _______________ _______________ _______________ _______________ _________
    CCNA

  12. #12
    Join Date
    Apr 2011
    Posts
    16

    Default

    D'oh! I realised that ISP wouldn't know how to ping going from ISP to Lab_B and Lab_C and back again. I don't know why I thought this way but I thought that the packets from Lab_B and Lab_C would give enough information to ISP to at least reach the next hop on the return path and from there...
    Anyway, thanks for the reply! I'll give it a shot with your suggestions. Much appreciated!

  13. #13
    Join Date
    Aug 2011
    Posts
    18

    Default problem with 13.1

    rip does not allow classless routing
    it allows only classful routing, right ? so it will allow us to ping between networks with default subnet masks

    so the /24 of 171.16.10.1 s/b changed to /16 isn't it ?

    am i correct ?
    gosh there is so much to remember, its been an avalanche after chapter 6

    rgds
    anek

  14. #14
    Join Date
    Dec 2011
    Posts
    4

    Default RIP V1 vs V2

    Quote Originally Posted by aneksadh View Post
    rip does not allow classless routing
    it allows only classful routing, right ? so it will allow us to ping between networks with default subnet masks

    so the /24 of 171.16.10.1 s/b changed to /16 isn't it ?

    am i correct ?
    gosh there is so much to remember, its been an avalanche after chapter 6

    rgds
    anek
    Look at the differences between version 1 and version 2 of RIP; you will find your answer there.

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