VLSM and EIGRP confussion

Discussion in 'General Computer Support' started by XtreZ, Jun 29, 2007.

  1. XtreZ


    Jun 29, 2007
    Likes Received:
    Hi. This is my first post here so please bear with me

    I currently have 2 Cisco routers, let's call them A and B, running IOS Version 12.1(8b)E19, which currently are currently running EIGRP and BGP between them. They are interlinked with 2 DS3's which do load balancing per packet. I have almost not problems in terms of routing troubleshooting, but this one has me puzzled.

    I have network subeneted in routers as follows: on router A on router B on router B on router B on router B on router B

    The only subnet I have a problem with is It seems that in spite of having the network configured as a /27 (it's added in one active interface as "ip address sec" ), the router only sees the ip as a /29. I can't ping anything beyond and .31 replies as a broadcast address.

    Furthermore, the routing table on both routers shows the first 8 ip's as members of a /27 block, but when ip check the route for and beyond, it does not appear in the routing table.

    Both routers have ip classless and ip subnet zero configured on them.

    Is there a way to make the complete subnet appear in the routing table? or is it just the way VLSM works? Im aware that it's best to use the first ips of the /24 for the larger subnets, but I did not configure this. Im just trying to troubleshoot it but so far I have not found any contrete info which explains why this happens.

    Both routers have eigrp configured as follows

    router eigrp 100
    no auto-summary
    redistribute connected
    no eigrp log-neighborgh-changes

    Can anybody explain why this is?

    Last edited: Jun 29, 2007
    XtreZ, Jun 29, 2007
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