From: Nitro Drops (nitrodrops@hotmail.com)
Date: Sun Jan 11 2009 - 11:26:51 ARST
Hi All,
Have been trying to fix my recursive routing for OSPF in the last 2 hours.
R1 F0/0 .1 >> 155.1.37.0 >> .2 F0/0 R2 F0/1 .2 >> 155.1.0.0 >> .3 F0/0 R3
GRE tunnel created between R1 and R3
R1
interface Tunnel0
ip address 155.1.57.1 255.255.255.0
tunnel source 155.1.37.1
tunnel destination 155.1.0.3
router ospf 1
network 155.1.0.0 0.0.255.255 area 0
distribute-list 2 in Tunnel0
access-list 2 deny 155.1.0.0 0.0.0.255
access-list 2 deny 155.1.37.0 0.0.0.255
access-list 2 permit any
R3
interface Tunnel0
ip address 155.1.57.3 255.255.255.0
tunnel source 155.1.0.3
tunnel destination 155.1.37.1
router ospf 1
network 155.1.0.0 0.0.255.255 area 0
distribute-list 2 in Tunnel0
access-list 2 deny 155.1.0.0 0.0.0.255
access-list 2 deny 155.1.37.0 0.0.0.255
access-list 2 permit any
To prevent recursive routing, i have used a distribute-list to prevent
learning the tunnel destination from the tunnel interface. However, my int
tunnel keeps on flapping (Debug IP routing as attached), did i missed out
anything on my configs or did i use the wrong method? I used the same method
on RIP & EIGRP, distribute-list works fine on both of them, distribute-list
applying in/out to stop the tunnel destination from advertising/learning from
the tunnel interface.
Except on OSPF, i can only prevent the router from learning from the tunnel
destination, CANT stop advertising the tunnel destination out of the tunnel
interface, as the OSPF distribute-list only works for inbound.
Cheers
Nit
IP routing debugging is on
R1#
*Mar 1 08:54:30.021: %OSPF-5-ADJCHG: Process 1, Nbr 15.2.2.2 on Tunnel0 from
LOADING to FULL, Loading Done
*Mar 1 08:54:41.541: RT: del 155.1.0.0/24 via 155.1.37.2, ospf metric
[110/120000]
*Mar 1 08:54:41.545: RT: delete subnet route to 155.1.0.0/24
*Mar 1 08:54:41.549: RT: NET-RED 155.1.0.0/24
*Mar 1 08:54:48.869: %LINEPROTO-5-UPDOWN: Line protocol on Interface Tunnel0,
changed state to down
*Mar 1 08:54:48.881: RT: is_up: Tunnel0 0 state: 4 sub state: 1 line: 0
has_route: True
*Mar 1 08:54:48.885: %OSPF-5-ADJCHG: Process 1, Nbr 15.2.2.2 on Tunnel0 from
FULL to DOWN, Neighbor Down: Interface down or detached
*Mar 1 08:54:48.893: RT: interface Tunnel0 removed from routing table
*Mar 1 08:54:48.893: RT: del 155.1.57.0/24 via 0.0.0.0, connected metric
[0/0]
*Mar 1 08:54:48.897: RT: delete subnet route to 155.1.57.0/24
*Mar 1 08:54:48.901: RT: NET-RED 155.1.57.0/24
*Mar 1 08:54:51.553: RT: SET_LAST_RDB for 155.1.0.0/24
NEW rdb: via 155.1.37.2
*Mar 1 08:54:51.561: RT: add 155.1.0.0/24 via 155.1.37.2, ospf metric
[110/120000]
*Mar 1 08:54:51.561: RT: NET-RED 155.1.0.0/24
*Mar 1 08:54:57.869: %LINEPROTO-5-UPDOWN: Line protocol on Interface Tunnel0,
changed state to up
*Mar 1 08:54:57.881: RT: is_up: Tunnel0 1 state: 4 sub state: 1 line: 0
has_route: False
*Mar 1 08:54:57.885: RT: SET_LAST_RDB for 155.1.57.0/24
NEW rdb: is directly connected
*Mar 1 08:54:57.889: RT: add 155.1.57.0/24 via 0.0.0.0, connected metric
[0/0]
*Mar 1 08:54:57.893: RT: NET-RED 155.1.57.0/24
*Mar 1 08:54:57.897: RT: interface Tunnel0 added to routing table
*Mar 1 08:54:58.973: %OSPF-5-ADJCHG: Process 1, Nbr 15.2.2.2 on Tunnel0 from
LOADING to FULL, Loading Done
*Mar 1 08:55:11.577: RT: del 155.1.0.0/24 via 155.1.37.2, ospf metric
[110/120000]
*Mar 1 08:55:11.581: RT: delete subnet route to 155.1.0.0/24
*Mar 1 08:55:11.585: RT: NET-RED 155.1.0.0/24
R1#undebug
*Mar 1 08:55:17.901: %OSPF-5-ADJCHG: Process 1, Nbr 15.2.2.2 on Tunnel0 from
FULL to DOWN, Neighbor Down: Interface down or detached
*Mar 1 08:55:18.869: %LINEPROTO-5-UPDOWN: Line protocol on Interface Tunnel0,
changed state to down
*Mar 1 08:55:18.877: RT: is_up: Tunnel0 0 state: 4 sub state: 1 line: 0
has_route: True
*Mar 1 08:55:18.881: RT: interface Tunnel0 removed from routing table
*Mar 1 08:55:18.885: RT: del 155.1.57.0/24 via 0.0.0.0, connected metric
[0/0]
*Mar 1 08:55:18.889: RT: delete subnet route to 155.1.57.0/24
*Mar 1 08:55:18.889: RT: NET-RED 155.1.57.0/24
R1#undebug al
*Mar 1 08:55:21.589: RT: SET_LAST_RDB for 155.1.0.0/24
NEW rdb: via 155.1.37.2
*Mar 1 08:55:21.597: RT: add 155.1.0.0/24 via 155.1.37.2, ospf metric
[110/120000]
*Mar 1 08:55:21.597: RT: NET-RED 155.1.0.0/24l
All possible debugging has been turned off
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