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Rip Problems

  • 28-04-2007 6:07pm
    #1
    Webmonkey
    Registered Users, Registered Users 2 Posts: 9,579 ✭✭✭


    Hi There,

    Just doing some lab work on 3 routers (cisco 2600s), 2 of which are connected to a top router via serial cables.
    We'll call these 3 routers: Gad, Anniston and Boaz.

    Anniston s0/0
    connected to
    s0/1 on Gad
    Boaz s0/0
    connected to
    s0/0 on Gad

    Configurations:

    Gad

    interface Serial0/0
    ip address 192.168.1.1 255.255.255.0
    no ip directed-broadcast
    clockrate 64000
    !
    interface Serial0/1
    ip address 192.168.101.1 255.255.255.0
    no ip directed-broadcast
    clockrate 64000

    Anniston

    interface FastEthernet0/0
    ip address 172.16.5.126 255.255.255.128
    no ip directed-broadcast
    !
    interface Serial0/0
    ip address 192.168.1.2 255.255.255.0

    Boaz

    interface FastEthernet0/0
    ip address 172.16.5.254 255.255.255.128
    no ip directed-broadcast
    !
    interface Serial0/0
    ip address 192.168.101.2 255.255.255.0


    The Hosts connect with the 172.16.0.0 network. This network is subnetted using 255.255.255.128 or 172.16.0.0/25

    I picked a sub network for each of Anniston and Boaz's f0/0 port:

    Anniston gets: 172.16.5.0 /25
    Boaz gets: 172.16.5.128 /25

    (I selected the last IP in the host range as the router/default gateway IP ,f0/0)

    Now attached to Anniston and Boaz's f0/0 interface is a simple switch. To this are 2 hosts on each switch.
    The hosts get IP's as well:

    Annistons two hosts get:
    172.16.5.1/25 DGateway: 172.16.5.126
    172.16.5.64/25 DGateway: 172.16.5.126

    Boaz two hosts get:
    172.16.5.129/25 DGateway: 172.16.5.254
    172.16.5.192/25 DGateway: 172.16.5.254

    Hope i havn't confused you now but this is my basic setup. If you really don't get what the layout here is, i'll throw up a diagram.

    Now everything works fine, Hosts can ping gateway, Anniston and Boaz can ping Gad and vice versa.

    The problem I have is in the routing, and hopefully someone can see where i going wrong.

    Gad's RIP configuration

    Gad(config):#router rip
    Gad(config-router):#network 192.168.1.0
    Gad(config-router):#network 192.168.101.0

    Anniston's RIP configuration

    Anniston(config):#router rip
    Anniston(config-router):#network 172.16.0.0
    Anniston(config-router):#network 172.16.0.0

    Boaz's RIP configuration

    Anniston(config):#router rip
    Anniston(config-router):#network 172.16.0.0
    Anniston(config-router):#network 172.16.0.0


    Now, I amn't sure what is going wrong but i can ping from the hosts on Anniston to the Boaz router, that as far as i can go and same with the other way around. I am totally confused. Only 60% of pings are successful too often when pinging from router to distant router. I am really confused.

    When configuring Anniston and Boaz's - am i right on putting the underlining network of 172.16.0.0. Should I put 172.16.5.0 and 172.16.5.128.

    Hopefully someone can shead bit of light on this!


Comments

  • #2
    Webmonkey
    Registered Users, Registered Users 2 Posts: 9,579 ✭✭✭Webmonkey


    Guess no one out there that can help?
    Pinging from Gad to the fast ethernet interfaces of Anniston and Boaz i get:

    Gad#ping 172.16.5.126

    Type escape sequence to abort.
    Sending 5, 100-byte ICMP Echos to 172.16.5.126, timeout is 2 seconds:
    !U!.!
    Success rate is 60 percent (3/5), round-trip min/avg/max = 28/28/28 ms

    This happens all the time, and same if I ping 172.16.5.254.

    Any ideas?


  • #3
    _CreeD_
    Registered Users, Registered Users 2 Posts: 4,162 ✭✭✭_CreeD_


    In the middle of something but off the top of my head you're using classless subnets, RIP does not support classless/VLSM/CIDR. Try RIP v2 or OSPF/EIGRP


  • #4
    Webmonkey
    Registered Users, Registered Users 2 Posts: 9,579 ✭✭✭Webmonkey


    Have ip classless command used.
    I decided to rebuild the whole thing on RouterSim and seems to work. Hope these things don't happen in my lab exam coming up next week now. Cheers for that.


  • #5
    _CreeD_
    Registered Users, Registered Users 2 Posts: 4,162 ✭✭✭_CreeD_


    IP Classless doesn't affect how RIP v1 operates though. It's a fundamental limitation of the routing protocol, it does not advertise subnet masks and assumes Classful rules at all times.


  • #6
    Webmonkey
    Registered Users, Registered Users 2 Posts: 9,579 ✭✭✭Webmonkey


    Sorry just realised that. My network lecture saying RIP v1 should be able to handle this scenario. I don't think so.
    Am i right in saying /8 /16 and /24 are classful and rest not?


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  • #7
    _CreeD_
    Registered Users, Registered Users 2 Posts: 4,162 ✭✭✭_CreeD_


    Your 192.168.x.0 ranges are fine as the subnet mask matches the class /24 . The 172.16.x.0 are the problem since it should be /16 which will make Boaz and Anniston both advertise that they have all of the 172.16.x.x range locally.
    TBH my CCNA stuff is getting rusty (spent much more time lately on the security side) but there is no way I can see that RIP v1 will allow for proper routing with those subnets. As a test try one of the others (excl. IGRP)


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