IGRP configuration

syntacticalerrorsyntacticalerror Member Posts: 15 ■□□□□□□□□□
in CCNA & CCENT
To all,

Heres my situation.......When setting up igrp, the network a.b.c.d command tells the router which networks on its interfaces will participate in the updates.......in theory....ha.

The cisco pressbook states: for the network connected to a interface that is specified in the Network command.........
1. The router broadcasts or multicast routing updates out an interface.
2. The router listens for incoming updates on that same interface.
3. The router, when sending and update, includes the subnet off that interface in the routing update.

My problem, when i run debug ip igrp, a particular interface (f0/1) i did NOT include in the Network command is sending updates from it.....violates 1. On an adjacent router when using Sh ip route, i see the route for the network on f0/0.....violates 3. Why is the first router including the network in the igrp protocol when i didn't specify it?.........much thanks for any help.
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Comments

  • sprinkl3ssprinkl3s Member Posts: 92 ■■□□□□□□□□
    can you post your config and ip route?
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  • mikearamamikearama Member Posts: 749
    How about showing us some of your config... particularly:

    sh ip protocols
    sh ip route
    sh ip igrp int

    and what was your network command when you turned on igrp?

    Oh, and is this on a live router? or on a sim?

    Mike
    There are only 10 kinds of people... those who understand binary, and those that don't.

    CCIE Studies: Written passed: Jan 21/12 Lab Prep: Hours reading: 385. Hours labbing: 110

    Taking a time-out to add the CCVP. Capitalizing on a current IPT pilot project.
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  • mikej412mikej412 Member Posts: 10,086 ■■■■■■■■■■
    What did you put in your network statement?
    What's the IP if that Fast Ethernet interface?
    What does the network statement in your configuration (show run) have?

    IGRP is classful

    If you put in
    network 10.0.1.0
    network 10.1.0.0
    network 10.253.254.0

    its going into the configuration as
    10.0.0.0
    :mike: Cisco Certifications -- Collect the Entire Set!
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  • shednikshednik Member Posts: 2,005
    it took me a few times to understand what you meant exactly...yes please post your configs without them its tough to tell exactly what the issue is. and like mike said igrp is classful so you may have specified it indirectly and that would be why its advertising...
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  • syntacticalerrorsyntacticalerror Member Posts: 15 ■□□□□□□□□□
    No problem....here are the outputs.

    I must clarify that there are four router connected together, but i've only enable igrp on two, which of course are the ones i'm talking about. Heres the diagram....lol.......

    ROUTER D (1.1.3.0)
    >>>switch d---->>console
    / \
    /(1.1.2.0) \(1.1.1.0)
    / \
    console<<<---(1.1.5.0)ROUTER A ROUTER B (1.1.6.0)---->>>switch b--->>>console
    \ /
    \(1.1.4.0) /(1.1.7.0)
    \ /
    ROUTER A(1.1.8.0)---->>switch a--->>>console

    As you can see router d is broadcasting 3.0 in its update and receiving 5.0 in its ip table. And vice versa, router a is broadcasting 5.0 in its update and receiving 3.0 in its ip table.

    Router>ena
    Router#sh ip prot
    Routing Protocol is "igrp 10"
    Sending updates every 90 seconds, next due in 49 seconds
    Invalid after 270 seconds, hold down 270, flushed after 630
    Outgoing update filter list for all interfaces is not set
    Incoming update filter list for all interfaces is not set
    Default networks flagged in outgoing updates
    Default networks accepted from incoming updates
    IGRP metric weight K1=1, K2=0, K3=1, K4=0, K5=0
    IGRP maximum hop count 100
    IGRP maximum metric variance 1
    Redistributing: igrp 10
    Routing for networks:
    1.1.2.0
    1.1.4.0
    Routing information sources:
    Gateway Distance Last Update
    1.1.2.1 100 00:00:41
    Distance: <default is 100>

    Router#sh ip rout
    Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
    D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
    N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
    E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
    i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate default
    U - per-user static route, o - ODR, P - periodic downloaded static route
    T - traffic engineered route

    Gateway of last resort is not set

    1.0.0.0/24 is subnetted, 5 subnets
    C 1.1.2.0 is directly connected, Serial0/0
    C 1.1.5.0 is directly connected, FastEthernet0/1
    I 1.1.1.0 [100/160250] via 1.1.2.1, 00:00:44, Serial0/0
    I 1.1.3.0 [100/160250] via 1.1.2.1, 00:00:44, Serial0/0
    C 1.1.4.0 is directly connected, Serial0/1
    Router#debug ip igrp
    % Incomplete command.
    Router#debug ip igrp eve
    IGRP event debugging is on
    Router#
    ld23h: IGRP: sending update to 255.255.255.255 via Serial0/0 <1.1.2.2>
    ld23h: IGRP: Update contains 2 interior, 0 system, and 0 exterior routes.
    ld23h: IGRP: Total routes in update: 2
    ld23h: IGRP: sending update to 255.255.255.255 via Serial0/0 <1.1.2.2>
    ld23h: IGRP: Update contains 2 interior, 0 system, and 0 exterior routes.
    ld23h: IGRP: Total routes in update: 2
    ld23h: IGRP: sending update to 255.255.255.255 via Serial0/0 <1.1.2.2>
    ld23h: IGRP: Update contains 2 interior, 0 system, and 0 exterior routes.
    ld23h: IGRP: Total routes in update: 2
    ld23h: IGRP: sending update to 255.255.255.255 via Serial0/1 <1.1.4.1>
    ld23h: IGRP: Update contains 2 interior, 0 system, and 0 exterior routes.
    ld23h: IGRP: Total routes in update: 2
    ld23h: IGRP: sending update to 255.255.255.255 via Serial0/1 <1.1.4.1>
    ld23h: IGRP: Update contains 2 interior, 0 system, and 0 exterior routes.
    ld23h: IGRP: Total routes in update: 2
    ld23h: IGRP: sending update to 255.255.255.255 via Serial0/1 <1.1.4.1>
    ld23h: IGRP: Update contains 2 interior, 0 system, and 0 exterior routes.
    ld23h: IGRP: Total routes in update: 2
    ld23h: IGRP: sending update to 255.255.255.255 via FastEthernet0/1 <1.1.5.1>
    ld23h: IGRP: Update contains 2 interior, 0 system, and 0 exterior routes.
    ld23h: IGRP: Total routes in update: 2
    ld23h: IGRP: sending update to 255.255.255.255 via FastEthernet0/1 <1.1.5.1>
    ld23h: IGRP: Update contains 2 interior, 0 system, and 0 exterior routes.
    ld23h: IGRP: Total routes in update: 2
    ld23h: IGRP: sending update to 255.255.255.255 via FastEthernet0/1 <1.1.5.1>
    ld23h: IGRP: Update contains 2 interior, 0 system, and 0 exterior routes.
    ld23h: IGRP: Total routes in update: 2



    Router>ena
    Router#sh ip proto
    Routing Protocol is "igrp 10"
    Sending updates every 90 seconds, next due in 32 seconds
    Invalid after 270 seconds, hold down 270, flushed after 630
    Outgoing update filter list for all interfaces is not set
    Incoming update filter list for all interfaces is not set
    Default networks flagged in outgoing updates
    Default networks accepted from incoming updates
    IGRP metric weight K1=1, K2=0, K3=1, K4=0, K5=0
    IGRP maximum hop count 100
    IGRP maximum metric variance 1
    Redistributing: igrp 10
    Routing for networks:
    1.1.1.0
    1.1.2.0
    Routing information sources:
    Gateway Distance Last Update
    1.1.2.2 100 00:00:58
    Distance: <default is 100>

    Router#sh ip rout
    Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
    D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
    N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
    E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
    i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate default
    U - per-user static route, o - ODR, P - periodic downloaded static route
    T - traffic engineered route

    Gateway of last resort is not set

    1.0.0.0/24 is subnetted, 5 subnets
    C 1.1.2.0 is directly connected, Serial0/1
    I 1.1.5.0 [100/160250] via 1.1.2.2, 00:01:12, Serial0/1
    C 1.1.1.0 is directly connected, Serial0/0
    C 1.1.3.0 is directly connected, FastEthernet0/0
    I 1.1.4.0 [100/160250] via 1.1.2.2, 00:01:12, Serial0/1
    Router#debug ip igrp eve
    IGRP event debugging is on
    Router#
    ld23h: IGRP: sending update to 255.255.255.255 via Serial0/0 <1.1.1.1>
    ld23h: IGRP: Update contains 2 interior, 0 system, and 0 exterior routes.
    ld23h: IGRP: Total routes in update: 2
    ld23h: IGRP: sending update to 255.255.255.255 via Serial0/0 <1.1.1.1>
    ld23h: IGRP: Update contains 2 interior, 0 system, and 0 exterior routes.
    ld23h: IGRP: Total routes in update: 2
    ld23h: IGRP: sending update to 255.255.255.255 via Serial0/0 <1.1.1.1>
    ld23h: IGRP: Update contains 2 interior, 0 system, and 0 exterior routes.
    ld23h: IGRP: Total routes in update: 2
    ld23h: IGRP: sending update to 255.255.255.255 via Serial0/1 <1.1.2.1>
    ld23h: IGRP: Update contains 2 interior, 0 system, and 0 exterior routes.
    ld23h: IGRP: Total routes in update: 2
    ld23h: IGRP: sending update to 255.255.255.255 via Serial0/1 <1.1.2.1>
    ld23h: IGRP: Update contains 2 interior, 0 system, and 0 exterior routes.
    ld23h: IGRP: Total routes in update: 2
    ld23h: IGRP: sending update to 255.255.255.255 via Serial0/1 <1.1.2.1>
    ld23h: IGRP: Update contains 2 interior, 0 system, and 0 exterior routes.
    ld23h: IGRP: Total routes in update: 2
    ld23h: IGRP: sending update to 255.255.255.255 via FastEthernet0/0 <1.1.3.1>
    ld23h: IGRP: Update contains 2 interior, 0 system, and 0 exterior routes.
    ld23h: IGRP: Total routes in update: 2
    ld23h: IGRP: sending update to 255.255.255.255 via FastEthernet0/0 <1.1.3.1>
    ld23h: IGRP: Update contains 2 interior, 0 system, and 0 exterior routes.
    ld23h: IGRP: Total routes in update: 2
    ld23h: IGRP: sending update to 255.255.255.255 via FastEthernet0/0 <1.1.3.1>
    ld23h: IGRP: Update contains 2 interior, 0 system, and 0 exterior routes.
    ld23h: IGRP: Total routes in update: 2
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  • syntacticalerrorsyntacticalerror Member Posts: 15 ■□□□□□□□□□
    sorry for the diagram gentleman, the format changed after the post.

    Command when setting up igrp.......
    conf#router igrp 10
    conf-router#network a.b.c.d



    Oh, and also i'm using Network Visualizer 5.0.
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  • syntacticalerrorsyntacticalerror Member Posts: 15 ■□□□□□□□□□
    alrite well, ha, so i guess igrp being classful is the problem. But then how can i prevent a certain network on an interface from being broadcasted.......or the only way to accomplish that is to use 1.0.0.0
    2.0.0.0
    3.0.0.0
    etc.
    etc??

    I think i just answered my question....should have figured it out myself....appreciate the information people.
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  • syntacticalerrorsyntacticalerror Member Posts: 15 ■□□□□□□□□□
    ok i guess the point here is igrp broadcast ALL subnets in a network address......you cannot specify which subnets to include in update and which to not. thanks again.
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  • sprinkl3ssprinkl3s Member Posts: 92 ■■□□□□□□□□
    you can use the passive-interface command to prevent an interface from advertising

    ETA: the Network on the interface will still be advertised out the other interfaces, but you can use access-lists to control what is coming in/out as well. the other option is to put that interface in a different classful network.
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