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BGP aggregates and IGRP default networks posted 01/15/2001
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Hi All,


I have one I cannot figure out. I have an IGRP router that is using a 
default-network to
overcome subnet mask length differences into my OSPF network. Works great 
until I
did the BGP part of the lab which requires an aggregate address. The 
aggregate address puts
a static route to null 0 in my routing table and I can no longer default 
route to the OSPF network:



OSPF Network with 24, 28 and 29 bit masks of 170.100.x.x
            |
           |
            |
     Router 5 - OSPF and IGRP
         |
         |     170.100.1.x/24
         |
       Frame-relay point-to-point link
         |
         |
         |
      Router 4 - running IGRP and BGP
                  ip default-network 200.0.5.0
            router bgp 5
               no auto-summary
              network 170.100.1.0 mask 255.255.255.0
                aggregate-address 170.0.0.0 255.0.0.0 summary-only


Now I get the following routing table on R4 and cannot get to any of the 
non 24 bit subnets in OSPF.
How do I fix WITHOUT using static routes on R5 that "summarize" the 28 and 
29 bit subnets to
24 bits and redistribute them into IGRP. Can I stop the aggregate address 
from being entered into
R4's routing table. I really only want to advertise that aggregate to my 
EBGP neighbor anyways.

Gateway of last resort is 170.100.1.5 to network 210.0.5.0

      170.100.0.0/24 is subnetted, 9 subnets
C       170.100.200.0 is directly connected, Ethernet0
I       170.100.233.0 [100/10476] via 170.100.1.5, 00:01:03, Serial0
I       170.100.129.0 [100/10476] via 170.100.1.5, 00:01:03, Serial0
I       170.100.150.0 [100/10476] via 170.100.1.5, 00:01:03, Serial0
I       170.100.68.0 [100/10476] via 170.100.1.5, 00:01:03, Serial0
I       170.100.67.0 [100/10476] via 170.100.1.5, 00:01:03, Serial0
I       170.100.64.0 [100/10476] via 170.100.1.5, 00:01:04, Serial0
I       170.100.65.0 [100/10476] via 170.100.1.5, 00:01:04, Serial0
C       170.100.1.0 is directly connected, Serial0
      1.0.0.0/24 is subnetted, 1 subnets
C       1.1.1.0 is directly connected, Loopback0
I*   210.0.5.0/24 [100/10476] via 170.100.1.5, 00:01:04, Serial0
B    205.15.150.0/24 [20/0] via 170.100.200.7, 1d18h
B    170.0.0.0/8 [200/0] via 0.0.0.0, 1d18h, Null0  <---------------this 
entry is stopping my default-network from being usefull.
tserve#ping 170.100.42.241

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 170.100.42.241, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)
tserve#


Thanks,

Julie Ann

------------------------------------------------------------------------
                                         Julie Ann Connary
           |           |                  Network Consulting Engineer
          |||         |||                  Federal Support Program
        .|||||.     .|||||.                 13635 Dulles Technology Drive, 
Herndon VA 20171
      .:|||||||||:.:|||||||||:.                 Pager: 1-888-642-0551
     c i s c o S y s t e m s     Email: jconnary@xxxxxxxxx

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