[nsp] EIGRP looping problem but not SIA ?

[Eric Kagan]

I have been battling a problem for 2 weeks which I originally thought was a
BGP problem (subnets flapping and getting dampened).  After stripping BGP to
bare config it didn't fix it and I stumbled across an EIGRP problem on those
same subnets.  Basically I have my BGP network statements being tied down
with Static Null routes (I will list config clips below).  It seems these
subnets are being advertised and re-distributed through EIGRP to all
neighbors and it is a loop.  I have read 100 docs, archive postings, etc and
I can't figure it out. Everything refers to SIA, but I have logging on and
don't have any error messages. Also, the actual neighbor sessions are not
getting reset (unless I reboot or clear them).  The strange part is it only
happens on certain subnets and not all of them.  There was some mention of
EIGRP routing loop bugs so I have upgraded IOS on all 3 of the the routers
as well. Here is a clip of the routers.  I am trying to only list relevant
info.  Any help or ideas would be greatly appreciated.  I am also willing to
work with someone offline on a consulting basis if interested.

Router A: 10.2.68.1 /28 (problem subnet is 10.2.68.0 /22.  It is connected
with Null route, yet show ip route show known from eigrp nei 172.5.228.134)

router eigrp 65555
 passive-interface FastEthernet0/0
 network 10.2.64.0 0.0.0.255
 network 10.2.65.0 0.0.0.255
 network 10.2.68.0 0.0.3.255
 no auto-summary
 eigrp log-neighbor-changes
!
router bgp 65555
 no synchronization
 bgp log-neighbor-changes
 network 10.2.68.0 mask 255.255.252.0
 network 10.2.88.0 mask 255.255.252.0
 network 10.2.95.0 mask 255.255.255.0

ip route 10.2.68.0 255.255.252.0 Null0 254
ip route 10.2.88.0 255.255.252.0 Null0 254
ip route 10.2.95.0 255.255.255.0 Null0 254

IP-EIGRP neighbors for process 65555
1   10.2.65.6             Fa4/0         13 00:37:19    1   200  0  26051
0   172.5.228.134     AT2/0.2       13 00:37:47    9   200  0  27618
2   10.2.68.5             Fa1/0         13 00:38:51    1   200  0  2386721

show ip rou 10.2.68.0 255.255.252.0
Routing entry for 10.2.68.0/22
  Known via "eigrp 65555", distance 90, metric 581120, type internal
  Redistributing via eigrp 65555
  Last update from 172.5.228.134 on ATM2/0.2, 00:01:04 ago
  Routing Descriptor Blocks:
  * 172.5.228.134, from 172.5.228.134, 00:01:04 ago, via ATM2/0.2
      Route metric is 581120, traffic share count is 1
      Total delay is 480 microseconds, minimum bandwidth is 4500 Kbit
      Reliability 255/255, minimum MTU 1500 bytes
      Loading 8/255, Hops 3


show ip eigrp top act
IP-EIGRP Topology Table for AS(65555)/ID(10.2.64.193)

Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
       r - reply Status, s - sia Status

A 10.2.68.0/22, 1 Successors, FD is 581120
    1 replies, active 00:00:39, query-origin: Clear
         via 10.2.65.6 (Infinity/Infinity), FastEthernet4/0, serno 3
       * via Redistributed (Infinity/Infinity)
      Remaining replies:
         via 172.5.228.134, r, ATM2/0.2


Router B: (10.2.64.1 /25) - The loop is -

IP-EIGRP neighbors for process 65555
2  10.2.64.2             Fa1/0         11 00:45:59    1   200  0  470103
1   10.2.65.2             AT2/0.1       12 00:46:00    1   200  0  27845
0   10.2.65.5             Fa4/0         14 00:46:01    1   200  0  30186

show ip rou 10.2.68.0 255.255.252.0
Routing entry for 10.2.68.0/22
  Known via "eigrp 65555", distance 90, metric 28160, type internal
  Redistributing via eigrp 65555
  Last update from 10.2.65.5 on FastEthernet4/0, 00:00:11 ago
  Routing Descriptor Blocks:
  * 10.2.65.5, from 10.2.65.5, 00:00:11 ago, via FastEthernet4/0
      Route metric is 28160, traffic share count is 1
      Total delay is 100 microseconds, minimum bandwidth is 100000 Kbit
      Reliability 255/255, minimum MTU 1500 bytes
      Loading 9/255, Hops 1


Router C (10.2.72.1 /27)

IP-EIGRP neighbors for process 65555

0   10.2.65.1             AT2/0.1       10 00:45:01   22   200  0  26205
2   172.5.228.133          AT2/0.2       12 00:45:34    8   200  0  30143
1   10.2.72.5             Fa1/0.1       14 00:45:37    1   200  0  3402274

show ip route 10.2.68.0 255.255.252.0
Routing entry for 10.2.68.0/22
  Known via "eigrp 65555", distance 90, metric 64256, type internal
  Redistributing via eigrp 65555
  Last update from 10.2.65.1 on ATM2/0.1, 00:00:54 ago
  Routing Descriptor Blocks:
  * 10.2.65.1, from 10.2.65.1, 00:00:54 ago, via ATM2/0.1
      Route metric is 64256, traffic share count is 1
      Total delay is 290 microseconds, minimum bandwidth is 45045 Kbit
      Reliability 255/255, minimum MTU 1500 bytes
      Loading 15/255, Hops 2

Hopefully that is enough config to get an idea of what is going on.  I tried
to post as little as possible while still being thorough.  I am welcome to
offline chat, ideas, etc and I am willing to hire someone for a few hours to
help troubleshoot and resolve.

Thanks
Eric