David Sudjiman

I’m doing InternetworkExpert WB 1 v5.0 5.20 EIGRP Filtering with Prefix-Lists. Actually, I’ve been doing it since last night but get stucked on R1 that’s not getting 3(0|1).[0-3].0.0 routes from R5. Well, InternetworkExpert should inform on the workbook that I need to remove the stub network form R5 so that R1 will receive route advertisement from it. But it was fun, though, that I could figure it out myself.

The second issue was that I needed to block 155.1.146.4/32 from advertising network 3(0|1).[0-3].0.0. It was actually pretty simple. Use the distribute-list prefix. So this is what I did.

Rack1R1#sh run |  s router eigrp
router eigrp 100
 timers active-time 1
 network 155.1.0.1 0.0.0.0
 network 155.1.13.1 0.0.0.0
 network 155.1.146.1 0.0.0.0
 metric weights 0 0 0 1 0 0
 distribute-list prefix PERMIT_ALL gateway NOT_FROM_R4 in
 auto-summary

Rack1R1#sh run | i prefix-list
ip prefix-list NOT_FROM_R4 seq 5 deny 155.1.46.4/32
ip prefix-list NOT_FROM_R4 seq 15 permit 0.0.0.0/0 le 32
ip prefix-list PERMIT_ALL seq 5 permit 0.0.0.0/0 le 32

Damn it! I’ve been spending hours to troubleshoot what the heck was wrong with the prefix-list and why there was no hit for 155.1.46.4/32!

Rack1R1#sh ip prefix-list d
Prefix-list with the last deletion/insertion: NOT_FROM_R4
ip prefix-list NOT_FROM_R4:
   count: 3, range entries: 1, sequences: 5 - 15, refcount: 3
   seq 5 deny 155.1.46.4/32 (hit count: 0, refcount: 2)
   seq 15 permit 0.0.0.0/0 le 32 (hit count: 8982, refcount: 1)
ip prefix-list PERMIT_ALL:
   count: 1, range entries: 1, sequences: 5 - 5, refcount: 2
   seq 5 permit 0.0.0.0/0 le 32 (hit count: 16082, refcount: 1)

Blind as bat! it should be 155.1.146.4/32 instead of 155.1.46.4/32.

Rack1R1(config)#do sh ip pref d
Prefix-list with the last deletion/insertion: NOT_FROM_R4
ip prefix-list NOT_FROM_R4:
   count: 3, range entries: 1, sequences: 5 - 15, refcount: 3
   seq 5 deny 155.1.146.4/32 (hit count: 26, refcount: 1)
   seq 10 deny 155.1.4.4/32 (hit count: 0, refcount: 2)
   seq 15 permit 0.0.0.0/0 le 32 (hit count: 10998, refcount: 1)
ip prefix-list PERMIT_ALL:
   count: 1, range entries: 1, sequences: 5 - 5, refcount: 2
   seq 5 permit 0.0.0.0/0 le 32 (hit count: 18124, refcount: 1)

Case closed, no brainer solution!