From: Luan Nguyen (luan.m.nguyen@gmail.com)
Date: Sat Jul 05 2008 - 20:18:03 ART
I assume you can't do debug stuffs since it's production routers?
I could put this in my lab later tonight and look...it seems very
interesting.
But in the mean time, while not route to null0 at a lower admin than EIGRP
and see what happen? who cares if it's 254 or 54 right?
-Luan
On Sat, Jul 5, 2008 at 6:20 PM, Joseph Brunner <joe@affirmedsystems.com>
wrote:
> Good afternoon,
>
>
>
> Perhaps someone can shed some light on this strange, vexing issue.
>
>
>
> Normally we are lead to believe that the "redistribute" command
> redistributes routes that are in the routing table using the protocol
> referenced by the redistribute command. However I have a situation where
> I'm
> running EBGP between two edge routers and the isp routers. These router DO
> NOT run IBGP between them. They DO run EIGRP between them. Eigrp is
> configured to redistribute bgp learned routes, so that the default route
> learned from the isp and redistributed to EIGRP learned internally.
>
>
>
> However the following is happening;
>
>
>
> 1. Eigrp is automatically redistributing the bgp holddown routes
> static
> to null0 (used to keep the routes in the bgp table permanently). Each Edge
> router is configured with identical static routes to null for the netblocks
> advertised into bgp.
> 2. The edge router with the the superior metric configured for the
> bgp-> eigrp redistribute command is becoming the router advertising these
> static routes into eigrp as external routes. So while eigrp is only
> configured with "redistribute bgp" they are indeed redistributing static
> routes (the hold down routes to null0), as IF THE "REDISTRIBUTE STATIC"
> command had been configured under router eigrp.
> 3. This is causing the "show ip bgp" output on the egde router picking
> up the eigrp static routes to list the other router's eigrp neighbor
> address
> as the "next hop" while is should be 0.0.0.0 (originated on this router).
> The EDGE router with the inferior metric in the "redistribute bgp" command
> under router eigrp see's this.
> 4. How is this possible?????!?!?! Why is "redistribute bgp 65000"
> under
> router eigrp matching the bgp table, not the routes know via bgp!
>
>
>
> Please check the below.
>
>
>
> NYCORPHQ1#show ip bgp
>
> BGP table version is 4, local router ID is 10.74.74.11
>
> Status codes: s suppressed, d damped, h history, * valid, > best, i -
> internal,
>
> r RIB-failure, S Stale
>
> Origin codes: i - IGP, e - EGP, ? - incomplete
>
>
>
> Network Next Hop Metric LocPrf Weight Path
>
> *> 0.0.0.0 66.66.1.1 0 0 11401 i
>
> *> 66.55.5.0/25 0.0.0.0 0 32768 i
>
> *> 66.55.5.128/25 0.0.0.0 0 32768 i
>
>
>
> NYCORPHQ1#show ip route
>
> Codes: 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
>
>
>
> Gateway of last resort is 66.66.1.1 to network 0.0.0.0
>
>
>
> 66.0.0.0/8 is variably subnetted, 3 subnets, 2 masks
>
> C 66.66.1.0/30 is directly connected, Serial0/0
>
> S 66.55.5.0/25 is directly connected, Null0
>
> S 66.55.5.128/25 is directly connected, Null0
>
> C 192.168.5.0/24 is directly connected, FastEthernet0/1
>
> 10.0.0.0/8 is variably subnetted, 7 subnets, 3 masks
>
> C 10.74.74.11/32 is directly connected, Loopback1
>
> D 10.74.74.12/32 [90/156160] via 10.10.10.2, 00:07:03,
> FastEthernet1/0
>
> C 10.10.10.0/24 is directly connected, FastEthernet1/0
>
> C 10.1.1.0/30 is directly connected, FastEthernet0/0
>
> D 10.74.74.1/32 [90/409600] via 10.1.1.2, 00:07:03, FastEthernet0/0
>
> D 10.1.1.4/30 [90/284160] via 10.10.10.2, 00:07:04, FastEthernet1/0
>
> D 10.254.0.0/24 [90/284160] via 10.1.1.2, 00:07:04, FastEthernet0/0
>
> B* 0.0.0.0/0 [20/0] via 66.66.1.1, 00:08:51
>
>
>
>
>
> NYCORPHQ2#show ip bgp
>
> BGP table version is 4, local router ID is 10.74.74.12
>
> Status codes: s suppressed, d damped, h history, * valid, > best, i -
> internal,
>
> r RIB-failure, S Stale
>
> Origin codes: i - IGP, e - EGP, ? - incomplete
>
>
>
> Network Next Hop Metric LocPrf Weight Path
>
> *> 0.0.0.0 66.66.2.1 0 0 11401 i
>
> *> 66.55.5.0/25 10.10.10.1 307200 32768 i
>
> *> 66.55.5.128/25 10.10.10.1 307200 32768 i
>
>
>
> NYCORPHQ2#show ip route
>
> Codes: 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
>
>
>
> Gateway of last resort is 66.66.2.1 to network 0.0.0.0
>
>
>
> 66.0.0.0/8 is variably subnetted, 3 subnets, 2 masks
>
> C 66.66.2.0/30 is directly connected, Serial1/0
>
> D EX 66.55.5.0/25 [170/307200] via 10.10.10.1, 00:06:35, Ethernet0/1
>
> D EX 66.55.5.128/25 [170/307200] via 10.10.10.1, 00:06:35, Ethernet0/1
>
> 10.0.0.0/8 is variably subnetted, 7 subnets, 3 masks
>
> D 10.74.74.11/32 [90/409600] via 10.10.10.1, 00:06:35, Ethernet0/1
>
> C 10.74.74.12/32 is directly connected, Loopback1
>
> C 10.10.10.0/24 is directly connected, Ethernet0/1
>
> D 10.1.1.0/30 [90/307200] via 10.10.10.1, 00:06:35, Ethernet0/1
>
> [90/307200] via 10.1.1.6, 00:06:35, Ethernet0/0
>
> D 10.74.74.1/32 [90/409600] via 10.1.1.6, 00:06:35, Ethernet0/0
>
> C 10.1.1.4/30 is directly connected, Ethernet0/0
>
> D 10.254.0.0/24 [90/284160] via 10.1.1.6, 00:06:35, Ethernet0/0
>
> B* 0.0.0.0/0 [20/0] via 66.66.2.1, 00:07:41
>
>
>
>
>
> NYCORPHQ1#show run
>
> interface FastEthernet0/0
>
> ip address 10.1.1.1 255.255.255.252
>
> duplex auto
>
> speed auto
>
> !
>
> interface Serial0/0
>
> ip address 66.66.1.2 255.255.255.252
>
> ip virtual-reassembly
>
> clock rate 2000000
>
> !
>
> interface FastEthernet1/0
>
> ip address 10.10.10.1 255.255.255.0
>
> ip virtual-reassembly
>
> speed 10
>
> full-duplex
>
> !
>
> router eigrp 10
>
> redistribute bgp 65000 metric 10000 100 255 1 1500
>
> network 10.0.0.0
>
> no auto-summary
>
> !
>
> router bgp 65000
>
> no synchronization
>
> bgp log-neighbor-changes
>
> network 66.55.5.0 mask 255.255.255.128
>
> network 66.55.5.128 mask 255.255.255.128
>
> neighbor 66.66.1.1 remote-as 11401
>
> neighbor 66.66.1.1 route-map nycorphq1 out
>
> no auto-summary
>
> !
>
> ip forward-protocol nd
>
> ip route 66.55.5.0 255.255.255.128 Null0 254
>
> ip route 66.55.5.128 255.255.255.128 Null0 254
>
> !
>
> !
>
> no ip http server
>
> no ip http secure-server
>
> !
>
> !
>
> ip prefix-list 66.55.5.0-25 seq 5 permit 66.55.5.0/25
>
> !
>
> ip prefix-list 66.55.5.128-25 seq 5 permit 66.55.5.128/25
>
> !
>
> route-map nycorphq1 permit 10
>
> match ip address prefix-list 66.55.5.0-25
>
> set metric 50
>
> !
>
> route-map nycorphq1 permit 20
>
> match ip address prefix-list 66.55.5.128-25
>
> set metric 500
>
> !
>
> !
>
> !
>
> !
>
> control-plane
>
> !
>
>
>
> NYCORPHQ2#show run
>
>
>
> !
>
> interface Ethernet0/0
>
> ip address 10.1.1.5 255.255.255.252
>
> half-duplex
>
> !
>
> interface Ethernet0/1
>
> ip address 10.10.10.2 255.255.255.0
>
> ip virtual-reassembly
>
> full-duplex
>
> !
>
> interface Ethernet0/2
>
> no ip address
>
> shutdown
>
> half-duplex
>
> !
>
> interface Ethernet0/3
>
> no ip address
>
> shutdown
>
> half-duplex
>
> !
>
> interface Serial1/0
>
> ip address 66.66.2.2 255.255.255.252
>
> ip virtual-reassembly
>
> serial restart-delay 0
>
> clock rate 2016000
>
> !
>
> interface Serial1/1
>
> no ip address
>
> shutdown
>
> serial restart-delay 0
>
> !
>
> interface Serial1/2
>
> no ip address
>
> shutdown
>
> serial restart-delay 0
>
> !
>
> interface Serial1/3
>
> no ip address
>
> shutdown
>
> serial restart-delay 0
>
> !
>
> router eigrp 10
>
> redistribute bgp 65000 metric 1500 100 255 1 1500
>
> network 10.0.0.0
>
> no auto-summary
>
> !
>
> router bgp 65000
>
> no synchronization
>
> bgp log-neighbor-changes
>
> network 66.55.5.0 mask 255.255.255.128
>
> network 66.55.5.128 mask 255.255.255.128
>
> neighbor 66.66.2.1 remote-as 11401
>
> neighbor 66.66.2.1 route-map nycorphq2 out
>
> no auto-summary
>
> !
>
> no ip http server
>
> no ip http secure-server
>
> !
>
> ip forward-protocol nd
>
> ip route 66.55.5.0 255.255.255.128 Null0 254
>
> ip route 66.55.5.128 255.255.255.128 Null0 254
>
> !
>
> !
>
> !
>
> ip prefix-list 66.55.5.0-25 seq 5 permit 66.55.5.0/25
>
> !
>
> ip prefix-list 66.55.5.128-25 seq 5 permit 66.55.5.128/25
>
> !
>
> route-map nycorphq2 permit 10
>
> match ip address prefix-list 66.55.5.128-25
>
> set metric 50
>
> !
>
> route-map nycorphq2 permit 20
>
> match ip address prefix-list 66.55.5.0-25
>
> set metric 500
>
> !
>
> !
>
> !
>
> control-plane
>
> !
>
> !
>
> !
>
> !
>
>
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This archive was generated by hypermail 2.1.4 : Mon Aug 04 2008 - 06:11:53 ART