0

So, I have the following topology.

A-B
| |
C-D

A-B-C-D are Routers. It doesn't matter what are the IP's of the interfaces. What matters is that I have 2 loopbacks for each router. 1.1.1.1 and 11.11.11.11 for router A // 2.2.2.2 and 22.22.22.22 for B // 3.3.3.3 and 33.33.33.33 for C // 4.4.4.4 and 44.44.44.44 for D.

I am running EIGRP for IP connectivity between devices.

My EIGRP configuration is 0.0.0.0 0.0.0.0 because if I would have used the exact configuration of interfaces I would not have this problem and I like to get in problems.

On top of EIGRP I am using iBGP.

How Routing Table looks like without Distribute List applied:

A#sh ip route
Codes: L - local, C - connected, S - static, 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
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
       a - application route
       + - replicated route, % - next hop override

Gateway of last resort is not set

      1.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        1.1.1.0/24 is directly connected, Loopback0
L        1.1.1.1/32 is directly connected, Loopback0
      2.0.0.0/24 is subnetted, 1 subnets
D        2.2.2.0 [90/409600] via 192.168.12.2, 00:00:35, Ethernet0/0
      3.0.0.0/24 is subnetted, 1 subnets
D        3.3.3.0 [90/409600] via 192.168.13.3, 00:00:35, Ethernet0/1
      4.0.0.0/24 is subnetted, 1 subnets
D        4.4.4.0 [90/435200] via 192.168.13.3, 00:00:35, Ethernet0/1
                 [90/435200] via 192.168.12.2, 00:00:35, Ethernet0/0
      11.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        11.11.11.0/24 is directly connected, Loopback1
L        11.11.11.11/32 is directly connected, Loopback1
      22.0.0.0/24 is subnetted, 1 subnets
D        22.22.22.0 [90/409600] via 192.168.12.2, 00:00:35, Ethernet0/0
      33.0.0.0/24 is subnetted, 1 subnets
D        33.33.33.0 [90/409600] via 192.168.13.3, 00:00:35, Ethernet0/1
      44.0.0.0/24 is subnetted, 1 subnets
D        44.44.44.0 [90/435200] via 192.168.13.3, 00:00:35, Ethernet0/1
                    [90/435200] via 192.168.12.2, 00:00:35, Ethernet0/0
      192.168.12.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.12.0/24 is directly connected, Ethernet0/0
L        192.168.12.1/32 is directly connected, Ethernet0/0
      192.168.13.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.13.0/24 is directly connected, Ethernet0/1
L        192.168.13.1/32 is directly connected, Ethernet0/1
D     192.168.24.0/24 [90/307200] via 192.168.12.2, 00:00:35, Ethernet0/0
D     192.168.34.0/24 [90/307200] via 192.168.13.3, 00:00:35, Ethernet0/1

Everything ok. I see Loopbacks advertised by EIGRP because 90 < 200.

Let's assume I want all my Loopbacks to be advertised by BGP and not EIGRP. Or at least, my EIGRP Loopbacks to be kept in Topology Table and not be promoted in Routing Table.

So, in order to do this, I created a distribute-list on router A to filter incoming EIGRP routes from all neighbors.

access-list 10 deny   2.2.2.0 0.0.0.255
access-list 10 deny   22.22.22.0 0.0.0.255
access-list 10 deny   3.3.3.0 0.0.0.255
access-list 10 deny   33.33.33.0 0.0.0.255
access-list 10 deny   4.4.4.0 0.0.0.255
access-list 10 deny   44.44.44.0 0.0.0.255


A#sh run | sec router eigrp
router eigrp 123
 distribute-list 10 in
 network 0.0.0.0


A#sh ip route
Codes: L - local, C - connected, S - static, 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
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
       a - application route
       + - replicated route, % - next hop override

Gateway of last resort is not set

      1.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        1.1.1.0/24 is directly connected, Loopback0
L        1.1.1.1/32 is directly connected, Loopback0
      2.0.0.0/24 is subnetted, 1 subnets
B        2.2.2.0 [200/0] via 192.168.12.2, 00:00:04
      3.0.0.0/24 is subnetted, 1 subnets
B        3.3.3.0 [200/0] via 192.168.13.3, 00:00:04
      4.0.0.0/24 is subnetted, 1 subnets
B        4.4.4.0 [200/0] via 192.168.34.4, 00:00:04
      11.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        11.11.11.0/24 is directly connected, Loopback1
L        11.11.11.11/32 is directly connected, Loopback1
      22.0.0.0/24 is subnetted, 1 subnets
B        22.22.22.0 [200/0] via 192.168.12.2, 00:00:04
      33.0.0.0/24 is subnetted, 1 subnets
B        33.33.33.0 [200/0] via 192.168.13.3, 00:00:04
      44.0.0.0/24 is subnetted, 1 subnets
B        44.44.44.0 [200/0] via 192.168.34.4, 00:00:04
      192.168.12.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.12.0/24 is directly connected, Ethernet0/0
L        192.168.12.1/32 is directly connected, Ethernet0/0
      192.168.13.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.13.0/24 is directly connected, Ethernet0/1
L        192.168.13.1/32 is directly connected, Ethernet0/1

So far, everything looks fine.

Now I am blocking my EIGRP routes and instead of those routes I see BGP routes in my routing table.

The problem is: now, if I remove just the 4.4.4.0 0.0.0.255 and 44.44.44.0 0.0.0.255 from my access-list and I keep only 2 and 3 loopbacks, my entire ip routing table looks like this

A#sh ip route
Codes: L - local, C - connected, S - static, 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
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
       a - application route
       + - replicated route, % - next hop override

Gateway of last resort is not set

      1.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        1.1.1.0/24 is directly connected, Loopback0
L        1.1.1.1/32 is directly connected, Loopback0
      2.0.0.0/24 is subnetted, 1 subnets
D        2.2.2.0 [90/409600] via 192.168.12.2, 00:01:19, Ethernet0/0
      3.0.0.0/24 is subnetted, 1 subnets
D        3.3.3.0 [90/409600] via 192.168.13.3, 00:01:19, Ethernet0/1
      4.0.0.0/24 is subnetted, 1 subnets
D        4.4.4.0 [90/435200] via 192.168.13.3, 00:01:19, Ethernet0/1
                 [90/435200] via 192.168.12.2, 00:01:19, Ethernet0/0
      11.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        11.11.11.0/24 is directly connected, Loopback1
L        11.11.11.11/32 is directly connected, Loopback1
      22.0.0.0/24 is subnetted, 1 subnets
D        22.22.22.0 [90/409600] via 192.168.12.2, 00:01:19, Ethernet0/0
      33.0.0.0/24 is subnetted, 1 subnets
D        33.33.33.0 [90/409600] via 192.168.13.3, 00:01:19, Ethernet0/1
      44.0.0.0/24 is subnetted, 1 subnets
D        44.44.44.0 [90/435200] via 192.168.13.3, 00:01:19, Ethernet0/1
                    [90/435200] via 192.168.12.2, 00:01:19, Ethernet0/0
      192.168.12.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.12.0/24 is directly connected, Ethernet0/0
L        192.168.12.1/32 is directly connected, Ethernet0/0
      192.168.13.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.13.0/24 is directly connected, Ethernet0/1
L        192.168.13.1/32 is directly connected, Ethernet0/1
D     192.168.24.0/24 [90/307200] via 192.168.12.2, 00:02:07, Ethernet0/0
D     192.168.34.0/24 [90/307200] via 192.168.13.3, 00:02:07, Ethernet0/1

Exactly. No BGP route. Even if I apply permit any at the end of the access-list, still nothing. Can anybody explain this behaviour.

LATE EDIT: If you wonder that I'm not using extended ACL with seq numbers, is because I specifically want to use standard access list and have my access-list be rewritten every single time I modify access-list. I want to get used with this kind of scenarios for further certifications.

3
  • Could you re-organize your post slightly so your question(s) are clearly expressed near the top, while keeping in-tact all the supporting information you have included below? May 24 at 20:54
  • 1
    Post your ACL in your last step. It may not be what you think it is.
    – Ron Trunk
    May 25 at 2:08
  • Yea, I am completely stupid. My ACL was rewritten with only the last 2 commands. So stupid...
    – Andrewy
    May 25 at 8:19

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